Commit Graph

6368 Commits

Author SHA1 Message Date
Steven Rostedt
9687bbf219 ftrace: Use guard to take the ftrace_lock in release_probe()
The ftrace_lock is held throughout the entire release_probe() function.
Use guard to simplify any exit paths.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/20241028071308.250787901@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-29 07:43:02 -04:00
Steven Rostedt
1432afb50d ftrace: Use guard to lock ftrace_lock in cache_mod()
The ftrace_lock is held throughout cache_mod(), use guard to simplify the
error paths.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/20241028071308.088458856@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-29 07:43:02 -04:00
Steven Rostedt
06294cf045 ftrace: Use guard for match_records()
The ftrace_lock is held for most of match_records() until the end of the
function. Use guard to make error paths simpler.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/20241028071307.927146604@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-29 07:43:02 -04:00
Steven Rostedt
6348a3fa72 fgraph: Use guard(mutex)(&ftrace_lock) for unregister_ftrace_graph()
The ftrace_lock is held throughout unregister_ftrace_graph(), use a guard
to simplify the error paths.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/20241028071307.770550792@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-29 07:43:02 -04:00
Steven Rostedt
434098485b fgraph: Give ret_stack its own kmem cache
The ret_stack (shadow stack used by function graph infrastructure) is
created for every task on the system when function graph is enabled. Give
it its own kmem_cache. This will make it easier to see how much memory is
being used specifically for function graph shadow stacks.

In the future, this size may change and may not be a power of two. Having
its own cache can also keep it from fragmenting memory.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Link: https://lore.kernel.org/20241026063210.7d4910a7@rorschach.local.home
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-29 07:43:02 -04:00
Steven Rostedt
6ea8b69da6 fgraph: Separate size of ret_stack from PAGE_SIZE
The ret_stack (shadow stack used by function graph infrastructure) is
currently defined as PAGE_SIZE. But some architectures which have 64K
PAGE_SIZE, this is way overkill. Also there's an effort to allow the
PAGE_SIZE to be defined at boot up.

Hard code it for now to 4096. In the future, this size may change and even
be dependent on specific architectures.

Link: https://lore.kernel.org/all/e5067bb8-0fcd-4739-9bca-0e872037d5a1@arm.com/

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241019152951.053f9646@rorschach.local.home
Suggested-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-29 07:43:01 -04:00
Steven Rostedt
81ec38ee9d Fixes for function graph:
- Fix missing mutex unlock in error path of register_ftrace_graph()
 
   A previous fix added a return on an error path and forgot to unlock the
   mutex. Instead of dealing with error paths, use guard(mutex) as the mutex
   is just released at the exit of the function anyway. Other functions
   in this file should be updated with this, but that's a cleanup and not
   a fix.
 
 - Change cpuhp setup name to be consistent with other cpuhp states
 
   The same fix that the above patch fixes added a cpuhp_setup_state() call
   with the name of "fgraph_idle_init". I was informed that it should instead
   be something like: "fgraph:online". Update that too.
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Merge tag 'ftrace-v6.12-rc4' into trace/ftrace/core

In order to modify the code that allocates the shadow stacks, merge the
changes that fixed the CPU hotplug shadow stack allocations and build on
top of that.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-29 07:31:50 -04:00
Linus Torvalds
f69a1accfe Fixes for function graph:
- Fix missing mutex unlock in error path of register_ftrace_graph()
 
   A previous fix added a return on an error path and forgot to unlock the
   mutex. Instead of dealing with error paths, use guard(mutex) as the mutex
   is just released at the exit of the function anyway. Other functions
   in this file should be updated with this, but that's a cleanup and not
   a fix.
 
 - Change cpuhp setup name to be consistent with other cpuhp states
 
   The same fix that the above patch fixes added a cpuhp_setup_state() call
   with the name of "fgraph_idle_init". I was informed that it should instead
   be something like: "fgraph:online". Update that too.
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Merge tag 'ftrace-v6.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ftrace fixes from Steven Rostedt:

 - Fix missing mutex unlock in error path of register_ftrace_graph()

   A previous fix added a return on an error path and forgot to unlock
   the mutex. Instead of dealing with error paths, use guard(mutex) as
   the mutex is just released at the exit of the function anyway. Other
   functions in this file should be updated with this, but that's a
   cleanup and not a fix.

 - Change cpuhp setup name to be consistent with other cpuhp states

   The same fix that the above patch fixes added a cpuhp_setup_state()
   call with the name of "fgraph_idle_init". I was informed that it
   should instead be something like: "fgraph:online". Update that too.

* tag 'ftrace-v6.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  fgraph: Change the name of cpuhp state to "fgraph:online"
  fgraph: Fix missing unlock in register_ftrace_graph()
2024-10-27 08:56:22 -10:00
Steven Rostedt
a574e7f80e fgraph: Change the name of cpuhp state to "fgraph:online"
The cpuhp state name given to cpuhp_setup_state() is "fgraph_idle_init"
which doesn't really conform to the names that are used for cpu hotplug
setups. Instead rename it to "fgraph:online" to be in line with other
states.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/20241024222944.473d88c5@rorschach.local.home
Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 2c02f7375e ("fgraph: Use CPU hotplug mechanism to initialize idle shadow stacks")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-24 23:41:14 -04:00
Li Huafei
bd3734db86 fgraph: Fix missing unlock in register_ftrace_graph()
Use guard(mutex)() to acquire and automatically release ftrace_lock,
fixing the issue of not unlocking when calling cpuhp_setup_state()
fails.

Fixes smatch warning:

kernel/trace/fgraph.c:1317 register_ftrace_graph() warn: inconsistent returns '&ftrace_lock'.

Link: https://lore.kernel.org/20241024155917.1019580-1-lihuafei1@huawei.com
Fixes: 2c02f7375e ("fgraph: Use CPU hotplug mechanism to initialize idle shadow stacks")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202410220121.wxg0olfd-lkp@intel.com/
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-24 22:26:06 -04:00
Alexei Starovoitov
bfa7b5c98b Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Cross-merge bpf fixes after downstream PR.

No conflicts.

Adjacent changes in:

include/linux/bpf.h
include/uapi/linux/bpf.h
kernel/bpf/btf.c
kernel/bpf/helpers.c
kernel/bpf/syscall.c
kernel/bpf/verifier.c
kernel/trace/bpf_trace.c
mm/slab_common.c
tools/include/uapi/linux/bpf.h
tools/testing/selftests/bpf/Makefile

Link: https://lore.kernel.org/all/20241024215724.60017-1-daniel@iogearbox.net/
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-10-24 18:47:28 -07:00
Linus Torvalds
ae90f6a617 BPF fixes:
- Fix an out-of-bounds read in bpf_link_show_fdinfo for BPF
   sockmap link file descriptors (Hou Tao)
 
 - Fix BPF arm64 JIT's address emission with tag-based KASAN
   enabled reserving not enough size (Peter Collingbourne)
 
 - Fix BPF verifier do_misc_fixups patching for inlining of the
   bpf_get_branch_snapshot BPF helper (Andrii Nakryiko)
 
 - Fix a BPF verifier bug and reject BPF program write attempts
   into read-only marked BPF maps (Daniel Borkmann)
 
 - Fix perf_event_detach_bpf_prog error handling by removing an
   invalid check which would skip BPF program release (Jiri Olsa)
 
 - Fix memory leak when parsing mount options for the BPF
   filesystem (Hou Tao)
 
 Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Pull bpf fixes from Daniel Borkmann:

 - Fix an out-of-bounds read in bpf_link_show_fdinfo for BPF sockmap
   link file descriptors (Hou Tao)

 - Fix BPF arm64 JIT's address emission with tag-based KASAN enabled
   reserving not enough size (Peter Collingbourne)

 - Fix BPF verifier do_misc_fixups patching for inlining of the
   bpf_get_branch_snapshot BPF helper (Andrii Nakryiko)

 - Fix a BPF verifier bug and reject BPF program write attempts into
   read-only marked BPF maps (Daniel Borkmann)

 - Fix perf_event_detach_bpf_prog error handling by removing an invalid
   check which would skip BPF program release (Jiri Olsa)

 - Fix memory leak when parsing mount options for the BPF filesystem
   (Hou Tao)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf: Check validity of link->type in bpf_link_show_fdinfo()
  bpf: Add the missing BPF_LINK_TYPE invocation for sockmap
  bpf: fix do_misc_fixups() for bpf_get_branch_snapshot()
  bpf,perf: Fix perf_event_detach_bpf_prog error handling
  selftests/bpf: Add test for passing in uninit mtu_len
  selftests/bpf: Add test for writes to .rodata
  bpf: Remove MEM_UNINIT from skb/xdp MTU helpers
  bpf: Fix overloading of MEM_UNINIT's meaning
  bpf: Add MEM_WRITE attribute
  bpf: Preserve param->string when parsing mount options
  bpf, arm64: Fix address emission with tag-based KASAN enabled
2024-10-24 16:53:20 -07:00
Jiri Olsa
0ee288e69d bpf,perf: Fix perf_event_detach_bpf_prog error handling
Peter reported that perf_event_detach_bpf_prog might skip to release
the bpf program for -ENOENT error from bpf_prog_array_copy.

This can't happen because bpf program is stored in perf event and is
detached and released only when perf event is freed.

Let's drop the -ENOENT check and make sure the bpf program is released
in any case.

Fixes: 170a7e3ea0 ("bpf: bpf_prog_array_copy() should return -ENOENT if exclude_prog not found")
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241023200352.3488610-1-jolsa@kernel.org

Closes: https://lore.kernel.org/lkml/20241022111638.GC16066@noisy.programming.kicks-ass.net/
2024-10-23 14:33:02 -07:00
Jiri Olsa
da09a9e0c3 uprobe: Add data pointer to consumer handlers
Adding data pointer to both entry and exit consumer handlers and all
its users. The functionality itself is coming in following change.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20241018202252.693462-2-jolsa@kernel.org
2024-10-23 20:52:27 +02:00
Leo Yan
0b6e2e22cb tracing: Consider the NULL character when validating the event length
strlen() returns a string length excluding the null byte. If the string
length equals to the maximum buffer length, the buffer will have no
space for the NULL terminating character.

This commit checks this condition and returns failure for it.

Link: https://lore.kernel.org/all/20241007144724.920954-1-leo.yan@arm.com/

Fixes: dec65d79fd ("tracing/probe: Check event name length correctly")
Signed-off-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-10-23 17:24:47 +09:00
Mikel Rychliski
73f3508047 tracing/probes: Fix MAX_TRACE_ARGS limit handling
When creating a trace_probe we would set nr_args prior to truncating the
arguments to MAX_TRACE_ARGS. However, we would only initialize arguments
up to the limit.

This caused invalid memory access when attempting to set up probes with
more than 128 fetchargs.

  BUG: kernel NULL pointer dereference, address: 0000000000000020
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: Oops: 0000 [#1] PREEMPT SMP PTI
  CPU: 0 UID: 0 PID: 1769 Comm: cat Not tainted 6.11.0-rc7+ #8
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-1.fc39 04/01/2014
  RIP: 0010:__set_print_fmt+0x134/0x330

Resolve the issue by applying the MAX_TRACE_ARGS limit earlier. Return
an error when there are too many arguments instead of silently
truncating.

Link: https://lore.kernel.org/all/20240930202656.292869-1-mikel@mikelr.com/

Fixes: 035ba76014 ("tracing/probes: cleanup: Set trace_probe::nr_args at trace_probe_init")
Signed-off-by: Mikel Rychliski <mikel@mikelr.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-10-23 17:24:44 +09:00
Daniel Borkmann
6fad274f06 bpf: Add MEM_WRITE attribute
Add a MEM_WRITE attribute for BPF helper functions which can be used in
bpf_func_proto to annotate an argument type in order to let the verifier
know that the helper writes into the memory passed as an argument. In
the past MEM_UNINIT has been (ab)used for this function, but the latter
merely tells the verifier that the passed memory can be uninitialized.

There have been bugs with overloading the latter but aside from that
there are also cases where the passed memory is read + written which
currently cannot be expressed, see also 4b3786a6c5 ("bpf: Zero former
ARG_PTR_TO_{LONG,INT} args in case of error").

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20241021152809.33343-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-10-22 15:42:56 -07:00
Puranjay Mohan
6280cf718d bpf: Implement bpf_send_signal_task() kfunc
Implement bpf_send_signal_task kfunc that is similar to
bpf_send_signal_thread and bpf_send_signal helpers  but can be used to
send signals to other threads and processes. It also supports sending a
cookie with the signal similar to sigqueue().

If the receiving process establishes a handler for the signal using the
SA_SIGINFO flag to sigaction(), then it can obtain this cookie via the
si_value field of the siginfo_t structure passed as the second argument
to the handler.

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241016084136.10305-2-puranjay@kernel.org
2024-10-21 15:02:49 -07:00
Qiao Ma
373b9338c9 uprobe: avoid out-of-bounds memory access of fetching args
Uprobe needs to fetch args into a percpu buffer, and then copy to ring
buffer to avoid non-atomic context problem.

Sometimes user-space strings, arrays can be very large, but the size of
percpu buffer is only page size. And store_trace_args() won't check
whether these data exceeds a single page or not, caused out-of-bounds
memory access.

It could be reproduced by following steps:
1. build kernel with CONFIG_KASAN enabled
2. save follow program as test.c

```
\#include <stdio.h>
\#include <stdlib.h>
\#include <string.h>

// If string length large than MAX_STRING_SIZE, the fetch_store_strlen()
// will return 0, cause __get_data_size() return shorter size, and
// store_trace_args() will not trigger out-of-bounds access.
// So make string length less than 4096.
\#define STRLEN 4093

void generate_string(char *str, int n)
{
    int i;
    for (i = 0; i < n; ++i)
    {
        char c = i % 26 + 'a';
        str[i] = c;
    }
    str[n-1] = '\0';
}

void print_string(char *str)
{
    printf("%s\n", str);
}

int main()
{
    char tmp[STRLEN];

    generate_string(tmp, STRLEN);
    print_string(tmp);

    return 0;
}
```
3. compile program
`gcc -o test test.c`

4. get the offset of `print_string()`
```
objdump -t test | grep -w print_string
0000000000401199 g     F .text  000000000000001b              print_string
```

5. configure uprobe with offset 0x1199
```
off=0x1199

cd /sys/kernel/debug/tracing/
echo "p /root/test:${off} arg1=+0(%di):ustring arg2=\$comm arg3=+0(%di):ustring"
 > uprobe_events
echo 1 > events/uprobes/enable
echo 1 > tracing_on
```

6. run `test`, and kasan will report error.
==================================================================
BUG: KASAN: use-after-free in strncpy_from_user+0x1d6/0x1f0
Write of size 8 at addr ffff88812311c004 by task test/499CPU: 0 UID: 0 PID: 499 Comm: test Not tainted 6.12.0-rc3+ #18
Hardware name: Red Hat KVM, BIOS 1.16.0-4.al8 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x55/0x70
 print_address_description.constprop.0+0x27/0x310
 kasan_report+0x10f/0x120
 ? strncpy_from_user+0x1d6/0x1f0
 strncpy_from_user+0x1d6/0x1f0
 ? rmqueue.constprop.0+0x70d/0x2ad0
 process_fetch_insn+0xb26/0x1470
 ? __pfx_process_fetch_insn+0x10/0x10
 ? _raw_spin_lock+0x85/0xe0
 ? __pfx__raw_spin_lock+0x10/0x10
 ? __pte_offset_map+0x1f/0x2d0
 ? unwind_next_frame+0xc5f/0x1f80
 ? arch_stack_walk+0x68/0xf0
 ? is_bpf_text_address+0x23/0x30
 ? kernel_text_address.part.0+0xbb/0xd0
 ? __kernel_text_address+0x66/0xb0
 ? unwind_get_return_address+0x5e/0xa0
 ? __pfx_stack_trace_consume_entry+0x10/0x10
 ? arch_stack_walk+0xa2/0xf0
 ? _raw_spin_lock_irqsave+0x8b/0xf0
 ? __pfx__raw_spin_lock_irqsave+0x10/0x10
 ? depot_alloc_stack+0x4c/0x1f0
 ? _raw_spin_unlock_irqrestore+0xe/0x30
 ? stack_depot_save_flags+0x35d/0x4f0
 ? kasan_save_stack+0x34/0x50
 ? kasan_save_stack+0x24/0x50
 ? mutex_lock+0x91/0xe0
 ? __pfx_mutex_lock+0x10/0x10
 prepare_uprobe_buffer.part.0+0x2cd/0x500
 uprobe_dispatcher+0x2c3/0x6a0
 ? __pfx_uprobe_dispatcher+0x10/0x10
 ? __kasan_slab_alloc+0x4d/0x90
 handler_chain+0xdd/0x3e0
 handle_swbp+0x26e/0x3d0
 ? __pfx_handle_swbp+0x10/0x10
 ? uprobe_pre_sstep_notifier+0x151/0x1b0
 irqentry_exit_to_user_mode+0xe2/0x1b0
 asm_exc_int3+0x39/0x40
RIP: 0033:0x401199
Code: 01 c2 0f b6 45 fb 88 02 83 45 fc 01 8b 45 fc 3b 45 e4 7c b7 8b 45 e4 48 98 48 8d 50 ff 48 8b 45 e8 48 01 d0 ce
RSP: 002b:00007ffdf00576a8 EFLAGS: 00000206
RAX: 00007ffdf00576b0 RBX: 0000000000000000 RCX: 0000000000000ff2
RDX: 0000000000000ffc RSI: 0000000000000ffd RDI: 00007ffdf00576b0
RBP: 00007ffdf00586b0 R08: 00007feb2f9c0d20 R09: 00007feb2f9c0d20
R10: 0000000000000001 R11: 0000000000000202 R12: 0000000000401040
R13: 00007ffdf0058780 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

This commit enforces the buffer's maxlen less than a page-size to avoid
store_trace_args() out-of-memory access.

Link: https://lore.kernel.org/all/20241015060148.1108331-1-mqaio@linux.alibaba.com/

Fixes: dcad1a204f ("tracing/uprobes: Fetch args before reserving a ring buffer")
Signed-off-by: Qiao Ma <mqaio@linux.alibaba.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-10-21 13:15:28 +09:00
Linus Torvalds
2b4d25010d - Add PREEMPT_RT maintainers
- Fix another aspect of delayed dequeued tasks wrt determining their state,
   i.e., whether they're runnable or blocked
 
 - Handle delayed dequeued tasks and their migration wrt PSI properly
 
 - Fix the situation where a delayed dequeue task gets enqueued into a new
   class, which should not happen
 
 - Fix a case where memory allocation would happen while the runqueue lock is
   held, which is a no-no
 
 - Do not over-schedule when tasks with shorter slices preempt the currently
   running task
 
 - Make sure delayed to deque entities are properly handled before unthrottling
 
 - Other smaller cleanups and improvements
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Merge tag 'sched_urgent_for_v6.12_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduling fixes from Borislav Petkov:

 - Add PREEMPT_RT maintainers

 - Fix another aspect of delayed dequeued tasks wrt determining their
   state, i.e., whether they're runnable or blocked

 - Handle delayed dequeued tasks and their migration wrt PSI properly

 - Fix the situation where a delayed dequeue task gets enqueued into a
   new class, which should not happen

 - Fix a case where memory allocation would happen while the runqueue
   lock is held, which is a no-no

 - Do not over-schedule when tasks with shorter slices preempt the
   currently running task

 - Make sure delayed to deque entities are properly handled before
   unthrottling

 - Other smaller cleanups and improvements

* tag 'sched_urgent_for_v6.12_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Add an entry for PREEMPT_RT.
  sched/fair: Fix external p->on_rq users
  sched/psi: Fix mistaken CPU pressure indication after corrupted task state bug
  sched/core: Dequeue PSI signals for blocked tasks that are delayed
  sched: Fix delayed_dequeue vs switched_from_fair()
  sched/core: Disable page allocation in task_tick_mm_cid()
  sched/deadline: Use hrtick_enabled_dl() before start_hrtick_dl()
  sched/eevdf: Fix wakeup-preempt by checking cfs_rq->nr_running
  sched: Fix sched_delayed vs cfs_bandwidth
2024-10-20 11:30:56 -07:00
Linus Torvalds
06526daaff ftrace: A couple of fixes to function graph infrastructure
- Fix allocation of idle shadow stack allocation during hotplug
 
   If function graph tracing is started when a CPU is offline, if it were
   come online during the trace then the idle task that represents the CPU
   will not get a shadow stack allocated for it. This means all function
   graph hooks that happen while that idle task is running (including in
   interrupt mode) will have all its events dropped.
 
   Switch over to the CPU hotplug mechanism that will have any newly
   brought on line CPU get a callback that can allocate the shadow stack
   for its idle task.
 
 - Fix allocation size of the ret_stack_list array
 
   When function graph tracing converted over to allowing more than one
   user at a time, it had to convert its shadow stack from an array of
   ret_stack structures to an array of unsigned longs. The shadow stacks
   are allocated in batches of 32 at a time and assigned to every running
   task. The batch is held by the ret_stack_list array. But when the
   conversion happened, instead of allocating an array of 32 pointers, it
   was allocated as a ret_stack itself (PAGE_SIZE). This ret_stack_list
   gets passed to a function that iterates over what it believes is its
   size defined by the FTRACE_RETSTACK_ALLOC_SIZE macro (which is 32).
 
   Luckily (PAGE_SIZE) is greater than 32 * sizeof(long), otherwise this
   would have been an array overflow. This still should be fixed and the
   ret_stack_list should be allocated to the size it is expected to be as
   someday it may end up being bigger than SHADOW_STACK_SIZE.
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Merge tag 'ftrace-v6.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ftrace fixes from Steven Rostedt:
 "A couple of fixes to function graph infrastructure:

   - Fix allocation of idle shadow stack allocation during hotplug

     If function graph tracing is started when a CPU is offline, if it
     were come online during the trace then the idle task that
     represents the CPU will not get a shadow stack allocated for it.
     This means all function graph hooks that happen while that idle
     task is running (including in interrupt mode) will have all its
     events dropped.

     Switch over to the CPU hotplug mechanism that will have any newly
     brought on line CPU get a callback that can allocate the shadow
     stack for its idle task.

   - Fix allocation size of the ret_stack_list array

     When function graph tracing converted over to allowing more than
     one user at a time, it had to convert its shadow stack from an
     array of ret_stack structures to an array of unsigned longs. The
     shadow stacks are allocated in batches of 32 at a time and assigned
     to every running task. The batch is held by the ret_stack_list
     array.

     But when the conversion happened, instead of allocating an array of
     32 pointers, it was allocated as a ret_stack itself (PAGE_SIZE).
     This ret_stack_list gets passed to a function that iterates over
     what it believes is its size defined by the
     FTRACE_RETSTACK_ALLOC_SIZE macro (which is 32).

     Luckily (PAGE_SIZE) is greater than 32 * sizeof(long), otherwise
     this would have been an array overflow. This still should be fixed
     and the ret_stack_list should be allocated to the size it is
     expected to be as someday it may end up being bigger than
     SHADOW_STACK_SIZE"

* tag 'ftrace-v6.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  fgraph: Allocate ret_stack_list with proper size
  fgraph: Use CPU hotplug mechanism to initialize idle shadow stacks
2024-10-19 12:42:14 -07:00
Thorsten Blum
514da6924e ring-buffer: Use str_low_high() helper in ring_buffer_producer()
Remove hard-coded strings by using the helper function str_low_high().

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241018110709.111707-2-thorsten.blum@linux.dev
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-19 11:12:25 -04:00
Julia Lawall
0b60a7fb60 ring-buffer: Reorganize kerneldoc parameter names
Reorganize kerneldoc parameter names to match the parameter
order in the function header.

Problems identified using Coccinelle.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240930112121.95324-22-Julia.Lawall@inria.fr
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-19 11:12:25 -04:00
Petr Pavlu
b237e1f7d2 ring-buffer: Limit time with disabled interrupts in rb_check_pages()
The function rb_check_pages() validates the integrity of a specified
per-CPU tracing ring buffer. It does so by traversing the underlying
linked list and checking its next and prev links.

To guarantee that the list isn't modified during the check, a caller
typically needs to take cpu_buffer->reader_lock. This prevents the check
from running concurrently, for example, with a potential reader which
can make the list temporarily inconsistent when swapping its old reader
page into the buffer.

A problem with this approach is that the time when interrupts are
disabled is non-deterministic, dependent on the ring buffer size. This
particularly affects PREEMPT_RT because the reader_lock is a raw
spinlock which doesn't become sleepable on PREEMPT_RT kernels.

Modify the check so it still attempts to traverse the entire list, but
gives up the reader_lock between checking individual pages. Introduce
for this purpose a new variable ring_buffer_per_cpu.cnt which is bumped
any time the list is modified. The value is used by rb_check_pages() to
detect such a change and restart the check.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241015112810.27203-1-petr.pavlu@suse.com
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-19 11:12:01 -04:00
Steven Rostedt
fae4078c28 fgraph: Allocate ret_stack_list with proper size
The ret_stack_list is an array of ret_stack shadow stacks for the function
graph usage. When the first function graph is enabled, all tasks in the
system get a shadow stack. The ret_stack_list is a 32 element array of
pointers to these shadow stacks. It allocates the shadow stack in batches
(32 stacks at a time), assigns them to running tasks, and continues until
all tasks are covered.

When the function graph shadow stack changed from an array of
ftrace_ret_stack structures to an array of longs, the allocation of
ret_stack_list went from allocating an array of 32 elements to just a
block defined by SHADOW_STACK_SIZE. Luckily, that's defined as PAGE_SIZE
and is much more than enough to hold 32 pointers. But it is way overkill
for the amount needed to allocate.

Change the allocation of ret_stack_list back to a kcalloc() of
FTRACE_RETSTACK_ALLOC_SIZE pointers.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241018215212.23f13f40@rorschach
Fixes: 42675b723b ("function_graph: Convert ret_stack to a series of longs")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-18 21:57:20 -04:00
Steven Rostedt
2c02f7375e fgraph: Use CPU hotplug mechanism to initialize idle shadow stacks
The function graph infrastructure allocates a shadow stack for every task
when enabled. This includes the idle tasks. The first time the function
graph is invoked, the shadow stacks are created and never freed until the
task exits. This includes the idle tasks.

Only the idle tasks that were for online CPUs had their shadow stacks
created when function graph tracing started. If function graph tracing is
enabled and a CPU comes online, the idle task representing that CPU will
not have its shadow stack created, and all function graph tracing for that
idle task will be silently dropped.

Instead, use the CPU hotplug mechanism to allocate the idle shadow stacks.
This will include idle tasks for CPUs that come online during tracing.

This issue can be reproduced by:

 # cd /sys/kernel/tracing
 # echo 0 > /sys/devices/system/cpu/cpu1/online
 # echo 0 > set_ftrace_pid
 # echo function_graph > current_tracer
 # echo 1 > options/funcgraph-proc
 # echo 1 > /sys/devices/system/cpu/cpu1
 # grep '<idle>' per_cpu/cpu1/trace | head

Before, nothing would show up.

After:
 1)    <idle>-0    |   0.811 us    |                        __enqueue_entity();
 1)    <idle>-0    |   5.626 us    |                      } /* enqueue_entity */
 1)    <idle>-0    |               |                      dl_server_update_idle_time() {
 1)    <idle>-0    |               |                        dl_scaled_delta_exec() {
 1)    <idle>-0    |   0.450 us    |                          arch_scale_cpu_capacity();
 1)    <idle>-0    |   1.242 us    |                        }
 1)    <idle>-0    |   1.908 us    |                      }
 1)    <idle>-0    |               |                      dl_server_start() {
 1)    <idle>-0    |               |                        enqueue_dl_entity() {
 1)    <idle>-0    |               |                          task_contending() {

Note, if tracing stops and restarts, the old way would then initialize
the onlined CPUs.

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/20241018214300.6df82178@rorschach
Fixes: 868baf07b1 ("ftrace: Fix memory leak with function graph and cpu hotplug")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-18 21:56:56 -04:00
Linus Torvalds
3d5ad2d4ec BPF fixes:
- Fix BPF verifier to not affect subreg_def marks in its range
   propagation, from Eduard Zingerman.
 
 - Fix a truncation bug in the BPF verifier's handling of
   coerce_reg_to_size_sx, from Dimitar Kanaliev.
 
 - Fix the BPF verifier's delta propagation between linked
   registers under 32-bit addition, from Daniel Borkmann.
 
 - Fix a NULL pointer dereference in BPF devmap due to missing
   rxq information, from Florian Kauer.
 
 - Fix a memory leak in bpf_core_apply, from Jiri Olsa.
 
 - Fix an UBSAN-reported array-index-out-of-bounds in BTF
   parsing for arrays of nested structs, from Hou Tao.
 
 - Fix build ID fetching where memory areas backing the file
   were created with memfd_secret, from Andrii Nakryiko.
 
 - Fix BPF task iterator tid filtering which was incorrectly
   using pid instead of tid, from Jordan Rome.
 
 - Several fixes for BPF sockmap and BPF sockhash redirection
   in combination with vsocks, from Michal Luczaj.
 
 - Fix riscv BPF JIT and make BPF_CMPXCHG fully ordered,
   from Andrea Parri.
 
 - Fix riscv BPF JIT under CONFIG_CFI_CLANG to prevent the
   possibility of an infinite BPF tailcall, from Pu Lehui.
 
 - Fix a build warning from resolve_btfids that bpf_lsm_key_free
   cannot be resolved, from Thomas Weißschuh.
 
 - Fix a bug in kfunc BTF caching for modules where the wrong
   BTF object was returned, from Toke Høiland-Jørgensen.
 
 - Fix a BPF selftest compilation error in cgroup-related tests
   with musl libc, from Tony Ambardar.
 
 - Several fixes to BPF link info dumps to fill missing fields,
   from Tyrone Wu.
 
 - Add BPF selftests for kfuncs from multiple modules, checking
   that the correct kfuncs are called, from Simon Sundberg.
 
 - Ensure that internal and user-facing bpf_redirect flags
   don't overlap, also from Toke Høiland-Jørgensen.
 
 - Switch to use kvzmalloc to allocate BPF verifier environment,
   from Rik van Riel.
 
 - Use raw_spinlock_t in BPF ringbuf to fix a sleep in atomic
   splat under RT, from Wander Lairson Costa.
 
 Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Pull bpf fixes from Daniel Borkmann:

 - Fix BPF verifier to not affect subreg_def marks in its range
   propagation (Eduard Zingerman)

 - Fix a truncation bug in the BPF verifier's handling of
   coerce_reg_to_size_sx (Dimitar Kanaliev)

 - Fix the BPF verifier's delta propagation between linked registers
   under 32-bit addition (Daniel Borkmann)

 - Fix a NULL pointer dereference in BPF devmap due to missing rxq
   information (Florian Kauer)

 - Fix a memory leak in bpf_core_apply (Jiri Olsa)

 - Fix an UBSAN-reported array-index-out-of-bounds in BTF parsing for
   arrays of nested structs (Hou Tao)

 - Fix build ID fetching where memory areas backing the file were
   created with memfd_secret (Andrii Nakryiko)

 - Fix BPF task iterator tid filtering which was incorrectly using pid
   instead of tid (Jordan Rome)

 - Several fixes for BPF sockmap and BPF sockhash redirection in
   combination with vsocks (Michal Luczaj)

 - Fix riscv BPF JIT and make BPF_CMPXCHG fully ordered (Andrea Parri)

 - Fix riscv BPF JIT under CONFIG_CFI_CLANG to prevent the possibility
   of an infinite BPF tailcall (Pu Lehui)

 - Fix a build warning from resolve_btfids that bpf_lsm_key_free cannot
   be resolved (Thomas Weißschuh)

 - Fix a bug in kfunc BTF caching for modules where the wrong BTF object
   was returned (Toke Høiland-Jørgensen)

 - Fix a BPF selftest compilation error in cgroup-related tests with
   musl libc (Tony Ambardar)

 - Several fixes to BPF link info dumps to fill missing fields (Tyrone
   Wu)

 - Add BPF selftests for kfuncs from multiple modules, checking that the
   correct kfuncs are called (Simon Sundberg)

 - Ensure that internal and user-facing bpf_redirect flags don't overlap
   (Toke Høiland-Jørgensen)

 - Switch to use kvzmalloc to allocate BPF verifier environment (Rik van
   Riel)

 - Use raw_spinlock_t in BPF ringbuf to fix a sleep in atomic splat
   under RT (Wander Lairson Costa)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: (38 commits)
  lib/buildid: Handle memfd_secret() files in build_id_parse()
  selftests/bpf: Add test case for delta propagation
  bpf: Fix print_reg_state's constant scalar dump
  bpf: Fix incorrect delta propagation between linked registers
  bpf: Properly test iter/task tid filtering
  bpf: Fix iter/task tid filtering
  riscv, bpf: Make BPF_CMPXCHG fully ordered
  bpf, vsock: Drop static vsock_bpf_prot initialization
  vsock: Update msg_count on read_skb()
  vsock: Update rx_bytes on read_skb()
  bpf, sockmap: SK_DROP on attempted redirects of unsupported af_vsock
  selftests/bpf: Add asserts for netfilter link info
  bpf: Fix link info netfilter flags to populate defrag flag
  selftests/bpf: Add test for sign extension in coerce_subreg_to_size_sx()
  selftests/bpf: Add test for truncation after sign extension in coerce_reg_to_size_sx()
  bpf: Fix truncation bug in coerce_reg_to_size_sx()
  selftests/bpf: Assert link info uprobe_multi count & path_size if unset
  bpf: Fix unpopulated path_size when uprobe_multi fields unset
  selftests/bpf: Fix cross-compiling urandom_read
  selftests/bpf: Add test for kfunc module order
  ...
2024-10-18 16:27:14 -07:00
Ingo Molnar
be602cde65 Merge branch 'linus' into sched/urgent, to resolve conflict
Conflicts:
	kernel/sched/ext.c

There's a context conflict between this upstream commit:

  3fdb9ebcec sched_ext: Start schedulers with consistent p->scx.slice values

... and this fix in sched/urgent:

  98442f0ccd sched: Fix delayed_dequeue vs switched_from_fair()

Resolve it.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2024-10-17 09:58:07 +02:00
Petr Pavlu
09661f75e7 ring-buffer: Fix reader locking when changing the sub buffer order
The function ring_buffer_subbuf_order_set() updates each
ring_buffer_per_cpu and installs new sub buffers that match the requested
page order. This operation may be invoked concurrently with readers that
rely on some of the modified data, such as the head bit (RB_PAGE_HEAD), or
the ring_buffer_per_cpu.pages and reader_page pointers. However, no
exclusive access is acquired by ring_buffer_subbuf_order_set(). Modifying
the mentioned data while a reader also operates on them can then result in
incorrect memory access and various crashes.

Fix the problem by taking the reader_lock when updating a specific
ring_buffer_per_cpu in ring_buffer_subbuf_order_set().

Link: https://lore.kernel.org/linux-trace-kernel/20240715145141.5528-1-petr.pavlu@suse.com/
Link: https://lore.kernel.org/linux-trace-kernel/20241010195849.2f77cc3f@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20241011112850.17212b25@gandalf.local.home/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241015112440.26987-1-petr.pavlu@suse.com
Fixes: 8e7b58c27b ("ring-buffer: Just update the subbuffers when changing their allocation order")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-15 11:18:51 -04:00
Steven Rostedt
2cf9733891 ring-buffer: Fix refcount setting of boot mapped buffers
A ring buffer which has its buffered mapped at boot up to fixed memory
should not be freed. Other buffers can be. The ref counting setup was
wrong for both. It made the not mapped buffers ref count have zero, and the
boot mapped buffer a ref count of 1. But an normally allocated buffer
should be 1, where it can be removed.

Keep the ref count of a normal boot buffer with its setup ref count (do
not decrement it), and increment the fixed memory boot mapped buffer's ref
count.

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241011165224.33dd2624@gandalf.local.home
Fixes: e645535a95 ("tracing: Add option to use memmapped memory for trace boot instance")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-14 14:30:59 -04:00
Peter Zijlstra
cd9626e9eb sched/fair: Fix external p->on_rq users
Sean noted that ever since commit 152e11f6df ("sched/fair: Implement
delayed dequeue") KVM's preemption notifiers have started
mis-classifying preemption vs blocking.

Notably p->on_rq is no longer sufficient to determine if a task is
runnable or blocked -- the aforementioned commit introduces tasks that
remain on the runqueue even through they will not run again, and
should be considered blocked for many cases.

Add the task_is_runnable() helper to classify things and audit all
external users of the p->on_rq state. Also add a few comments.

Fixes: 152e11f6df ("sched/fair: Implement delayed dequeue")
Reported-by: Sean Christopherson <seanjc@google.com>
Tested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20241010091843.GK33184@noisy.programming.kicks-ass.net
2024-10-14 09:14:35 +02:00
Tyrone Wu
ad6b5b6ea9 bpf: Fix unpopulated path_size when uprobe_multi fields unset
Previously when retrieving `bpf_link_info.uprobe_multi` with `path` and
`path_size` fields unset, the `path_size` field is not populated
(remains 0). This behavior was inconsistent with how other input/output
string buffer fields work, as the field should be populated in cases
when:
- both buffer and length are set (currently works as expected)
- both buffer and length are unset (not working as expected)

This patch now fills the `path_size` field when `path` and `path_size`
are unset.

Fixes: e56fdbfb06 ("bpf: Add link_info support for uprobe multi link")
Signed-off-by: Tyrone Wu <wudevelops@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241011000803.681190-1-wudevelops@gmail.com
2024-10-10 19:11:28 -07:00
Steven Rostedt
7888af4166 ftrace: Make ftrace_regs abstract from direct use
ftrace_regs was created to hold registers that store information to save
function parameters, return value and stack. Since it is a subset of
pt_regs, it should only be used by its accessor functions. But because
pt_regs can easily be taken from ftrace_regs (on most archs), it is
tempting to use it directly. But when running on other architectures, it
may fail to build or worse, build but crash the kernel!

Instead, make struct ftrace_regs an empty structure and have the
architectures define __arch_ftrace_regs and all the accessor functions
will typecast to it to get to the actual fields. This will help avoid
usage of ftrace_regs directly.

Link: https://lore.kernel.org/all/20241007171027.629bdafd@gandalf.local.home/

Cc: "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>
Cc: "x86@kernel.org" <x86@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Paul  Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas  Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav  Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/20241008230628.958778821@goodmis.org
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-10 20:18:01 -04:00
Steven Rostedt
c73eb02a47 fgragh: No need to invoke the function call_filter_check_discard()
The function call_filter_check_discard() has been removed in the
commit 49e4154f4b ("tracing: Remove TRACE_EVENT_FL_FILTERED logic"),
from another topic branch. But when merged together with commit
21e92806d3 ("function_graph: Support recording and printing the
function return address") which added another call to
call_filter_check_discard(), it caused the build to fail. Since the
function call_filter_check_discard() is useless, it can simply be removed
regardless of being merged with commit 49e4154f4b or not.

Link: https://lore.kernel.org/all/20241010134649.43ed357c@canb.auug.org.au/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Donglin Peng <dolinux.peng@gmail.com>
Link: https://lore.kernel.org/20241010194020.46192b21@gandalf.local.home
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 21e92806d3 ("function_graph: Support recording and printing the function return address")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-10 19:49:41 -04:00
Masami Hiramatsu (Google)
0a6c61bc9c fgraph: Simplify return address printing in function graph tracer
Simplify return address printing in the function graph tracer by removing
fgraph_extras. Since this feature is only used by the function graph
tracer and the feature flags can directly accessible from the function
graph tracer, fgraph_extras can be removed from the fgraph callback.

Cc: Donglin Peng <dolinux.peng@gmail.com>
Link: https://lore.kernel.org/172857234900.270774.15378354017601069781.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-10 14:06:26 -04:00
Uros Bizjak
eb887c4567 tracing: Use atomic64_inc_return() in trace_clock_counter()
Use atomic64_inc_return(&ref) instead of atomic64_add_return(1, &ref)
to use optimized implementation and ease register pressure around
the primitive for targets that implement optimized variant.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241007085651.48544-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-09 19:59:49 -04:00
Levi Yun
afe5960dc2 trace/trace_event_perf: remove duplicate samples on the first tracepoint event
When a tracepoint event is created with attr.freq = 1,
'hwc->period_left' is not initialized correctly. As a result,
in the perf_swevent_overflow() function, when the first time the event occurs,
it calculates the event overflow and the perf_swevent_set_period() returns 3,
this leads to the event are recorded for three duplicate times.

Step to reproduce:
    1. Enable the tracepoint event & starting tracing
         $ echo 1 > /sys/kernel/tracing/events/module/module_free
         $ echo 1 > /sys/kernel/tracing/tracing_on

    2. Record with perf
         $ perf record -a --strict-freq -F 1 -e "module:module_free"

    3. Trigger module_free event.
         $ modprobe -i sunrpc
         $ modprobe -r sunrpc

Result:
     - Trace pipe result:
         $ cat trace_pipe
         modprobe-174509  [003] .....  6504.868896: module_free: sunrpc

     - perf sample:
         modprobe  174509 [003]  6504.868980: module:module_free: sunrpc
         modprobe  174509 [003]  6504.868980: module:module_free: sunrpc
         modprobe  174509 [003]  6504.868980: module:module_free: sunrpc

By setting period_left via perf_swevent_set_period() as other sw_event did,
This problem could be solved.

After patch:
     - Trace pipe result:
         $ cat trace_pipe
         modprobe 1153096 [068] 613468.867774: module:module_free: xfs

     - perf sample
         modprobe 1153096 [068] 613468.867794: module:module_free: xfs

Link: https://lore.kernel.org/20240913021347.595330-1-yeoreum.yun@arm.com
Fixes: bd2b5b1284 ("perf_counter: More aggressive frequency adjustment")
Signed-off-by: Levi Yun <yeoreum.yun@arm.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-09 19:44:54 -04:00
Mathieu Desnoyers
cdb537ac41 tracing/perf: Add might_fault check to syscall probes
Add a might_fault() check to validate that the perf sys_enter/sys_exit
probe callbacks are indeed called from a context where page faults can
be handled.

Cc: Michael Jeanson <mjeanson@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: bpf@vger.kernel.org
Cc: Joel Fernandes <joel@joelfernandes.org>
Link: https://lore.kernel.org/20241009010718.2050182-8-mathieu.desnoyers@efficios.com
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-09 17:09:46 -04:00
Mathieu Desnoyers
a3204c740a tracing/ftrace: Add might_fault check to syscall probes
Add a might_fault() check to validate that the ftrace sys_enter/sys_exit
probe callbacks are indeed called from a context where page faults can
be handled.

Cc: Michael Jeanson <mjeanson@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: bpf@vger.kernel.org
Cc: Joel Fernandes <joel@joelfernandes.org>
Link: https://lore.kernel.org/20241009010718.2050182-7-mathieu.desnoyers@efficios.com
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-09 17:09:36 -04:00
Mathieu Desnoyers
65e7462a16 tracing/perf: disable preemption in syscall probe
In preparation for allowing system call enter/exit instrumentation to
handle page faults, make sure that perf can handle this change by
explicitly disabling preemption within the perf system call tracepoint
probes to respect the current expectations within perf ring buffer code.

This change does not yet allow perf to take page faults per se within
its probe, but allows its existing probes to adapt to the upcoming
change.

Cc: Michael Jeanson <mjeanson@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: bpf@vger.kernel.org
Cc: Joel Fernandes <joel@joelfernandes.org>
Link: https://lore.kernel.org/20241009010718.2050182-4-mathieu.desnoyers@efficios.com
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-09 17:07:25 -04:00
Mathieu Desnoyers
13d750c2c0 tracing/ftrace: disable preemption in syscall probe
In preparation for allowing system call enter/exit instrumentation to
handle page faults, make sure that ftrace can handle this change by
explicitly disabling preemption within the ftrace system call tracepoint
probes to respect the current expectations within ftrace ring buffer
code.

This change does not yet allow ftrace to take page faults per se within
its probe, but allows its existing probes to adapt to the upcoming
change.

Cc: Michael Jeanson <mjeanson@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: bpf@vger.kernel.org
Cc: Joel Fernandes <joel@joelfernandes.org>
Link: https://lore.kernel.org/20241009010718.2050182-3-mathieu.desnoyers@efficios.com
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-09 17:07:00 -04:00
Steven Rostedt
912da2c384 ring-buffer: Do not have boot mapped buffers hook to CPU hotplug
The boot mapped ring buffer has its buffer mapped at a fixed location
found at boot up. It is not dynamic. It cannot grow or be expanded when
new CPUs come online.

Do not hook fixed memory mapped ring buffers to the CPU hotplug callback,
otherwise it can cause a crash when it tries to add the buffer to the
memory that is already fully occupied.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241008143242.25e20801@gandalf.local.home
Fixes: be68d63a13 ("ring-buffer: Add ring_buffer_alloc_range()")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-09 09:24:35 -04:00
Steven Rostedt
48bcda6848 tracing: Remove definition of trace_*_rcuidle()
The trace_*_rcuidle() variant of a tracepoint was to handle places where a
tracepoint was located but RCU was not "watching". All those locations
have been removed, and RCU should be watching where all tracepoints are
located. We can now remove the trace_*_rcuidle() variant.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Link: https://lore.kernel.org/20241003181629.36209057@gandalf.local.home
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-08 21:17:39 -04:00
Josh Poimboeuf
4a8840af5f tracepoints: Use new static branch API
The old static key API is deprecated.  Switch to the new one.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/7a08dae3c5eddb14b13864923c1b58ac1f4af83c.1728414936.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-08 21:17:39 -04:00
Zheng Yejian
49e4154f4b tracing: Remove TRACE_EVENT_FL_FILTERED logic
After commit dcb0b5575d ("tracing: Remove TRACE_EVENT_FL_USE_CALL_FILTER
 logic"), no one's going to set the TRACE_EVENT_FL_FILTERED or change the
call->filter, so remove related logic.

Link: https://lore.kernel.org/20240911010026.2302849-1-zhengyejian@huaweicloud.com
Signed-off-by: Zheng Yejian <zhengyejian@huaweicloud.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-08 15:24:49 -04:00
Justin Stitt
2aa746ec02 tracing/branch-profiler: Replace deprecated strncpy with strscpy
strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

Both of these fields want to be NUL-terminated as per their use in
printk:

    F_printk("%u:%s:%s (%u)%s",
      __entry->line,
      __entry->func, __entry->file, __entry->correct,
      __entry->constant ? " CONSTANT" : "")

Use strscpy() as it NUL-terminates the destination buffer, so it doesn't
have to be done manually.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/20240826-strncpy-kernel-trace-trace_branch-c-v1-1-b2c14f2e9e84@google.com
Signed-off-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-08 15:24:38 -04:00
Li Chen
e32540b1e4 ftrace: Use this_cpu_ptr() instead of per_cpu_ptr(smp_processor_id())
Use this_cpu_ptr() instead of open coding the equivalent in various
ftrace functions.

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/87y14t6ofi.wl-me@linux.beauty
Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-08 15:24:22 -04:00
Oleg Nesterov
474ec3e849 function_graph: Remove unnecessary initialization in ftrace_graph_ret_addr()
After the commit 29c1c24a27 ("function_graph: Fix up ftrace_graph_ret_addr()")
ftrace_graph_ret_addr() doesn't need to initialize "int i" at the start.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/20240916175818.GA28944@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-05 10:14:04 -04:00
Donglin Peng
21e92806d3 function_graph: Support recording and printing the function return address
When using function_graph tracer to analyze the flow of kernel function
execution, it is often necessary to quickly locate the exact line of code
where the call occurs. While this may be easy at times, it can be more
time-consuming when some functions are inlined or the flow is too long.

This feature aims to simplify the process by recording the return address
of traced funcions and printing it when outputing trace logs.

To enhance human readability, the prefix 'ret=' is used for the kernel return
value, while '<-' serves as the prefix for the return address in trace logs to
make it look more like the function tracer.

A new trace option named 'funcgraph-retaddr' has been introduced, and the
existing option 'sym-addr' can be used to control the format of the return
address.

See below logs with both funcgraph-retval and funcgraph-retaddr enabled.

0)             | load_elf_binary() { /* <-bprm_execve+0x249/0x600 */
0)             |   load_elf_phdrs() { /* <-load_elf_binary+0x84/0x1730 */
0)             |     __kmalloc_noprof() { /* <-load_elf_phdrs+0x4a/0xb0 */
0)   3.657 us  |       __cond_resched(); /* <-__kmalloc_noprof+0x28c/0x390 ret=0x0 */
0) + 24.335 us |     } /* __kmalloc_noprof ret=0xffff8882007f3000 */
0)             |     kernel_read() { /* <-load_elf_phdrs+0x6c/0xb0 */
0)             |       rw_verify_area() { /* <-kernel_read+0x2b/0x50 */
0)             |         security_file_permission() { /* <-kernel_read+0x2b/0x50 */
0)             |           selinux_file_permission() { /* <-security_file_permission+0x26/0x40 */
0)             |             __inode_security_revalidate() { /* <-selinux_file_permission+0x6d/0x140 */
0)   2.034 us  |               __cond_resched(); /* <-__inode_security_revalidate+0x5f/0x80 ret=0x0 */
0)   6.602 us  |             } /* __inode_security_revalidate ret=0x0 */
0)   2.214 us  |             avc_policy_seqno(); /* <-selinux_file_permission+0x107/0x140 ret=0x0 */
0) + 16.670 us |           } /* selinux_file_permission ret=0x0 */
0) + 20.809 us |         } /* security_file_permission ret=0x0 */
0) + 25.217 us |       } /* rw_verify_area ret=0x0 */
0)             |       __kernel_read() { /* <-load_elf_phdrs+0x6c/0xb0 */
0)             |         ext4_file_read_iter() { /* <-__kernel_read+0x160/0x2e0 */

Then, we can use the faddr2line to locate the source code, for example:

$ ./scripts/faddr2line ./vmlinux load_elf_phdrs+0x6c/0xb0
load_elf_phdrs+0x6c/0xb0:
elf_read at fs/binfmt_elf.c:471
(inlined by) load_elf_phdrs at fs/binfmt_elf.c:531

Link: https://lore.kernel.org/20240915032912.1118397-1-dolinux.peng@gmail.com
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202409150605.HgUmU8ea-lkp@intel.com/
Signed-off-by: Donglin Peng <dolinux.peng@gmail.com>
[ Rebased to handle text_delta offsets ]
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-05 10:14:04 -04:00
Andrew Kreimer
ac1987f8f5 rv: Fix a typo
Fix a typo in comments.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240911114349.20449-1-algonell@gmail.com
Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Kreimer <algonell@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-04 19:09:23 -04:00
Wei Li
2a13ca2e8a tracing/hwlat: Fix a race during cpuhp processing
The cpuhp online/offline processing race also exists in percpu-mode hwlat
tracer in theory, apply the fix too. That is:

    T1                       | T2
    [CPUHP_ONLINE]           | cpu_device_down()
     hwlat_hotplug_workfn()  |
                             |     cpus_write_lock()
                             |     takedown_cpu(1)
                             |     cpus_write_unlock()
    [CPUHP_OFFLINE]          |
        cpus_read_lock()     |
        start_kthread(1)     |
        cpus_read_unlock()   |

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240924094515.3561410-5-liwei391@huawei.com
Fixes: ba998f7d95 ("trace/hwlat: Support hotplug operations")
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-03 16:43:23 -04:00
Wei Li
829e0c9f08 tracing/timerlat: Fix a race during cpuhp processing
There is another found exception that the "timerlat/1" thread was
scheduled on CPU0, and lead to timer corruption finally:

```
ODEBUG: init active (active state 0) object: ffff888237c2e108 object type: hrtimer hint: timerlat_irq+0x0/0x220
WARNING: CPU: 0 PID: 426 at lib/debugobjects.c:518 debug_print_object+0x7d/0xb0
Modules linked in:
CPU: 0 UID: 0 PID: 426 Comm: timerlat/1 Not tainted 6.11.0-rc7+ #45
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:debug_print_object+0x7d/0xb0
...
Call Trace:
 <TASK>
 ? __warn+0x7c/0x110
 ? debug_print_object+0x7d/0xb0
 ? report_bug+0xf1/0x1d0
 ? prb_read_valid+0x17/0x20
 ? handle_bug+0x3f/0x70
 ? exc_invalid_op+0x13/0x60
 ? asm_exc_invalid_op+0x16/0x20
 ? debug_print_object+0x7d/0xb0
 ? debug_print_object+0x7d/0xb0
 ? __pfx_timerlat_irq+0x10/0x10
 __debug_object_init+0x110/0x150
 hrtimer_init+0x1d/0x60
 timerlat_main+0xab/0x2d0
 ? __pfx_timerlat_main+0x10/0x10
 kthread+0xb7/0xe0
 ? __pfx_kthread+0x10/0x10
 ret_from_fork+0x2d/0x40
 ? __pfx_kthread+0x10/0x10
 ret_from_fork_asm+0x1a/0x30
 </TASK>
```

After tracing the scheduling event, it was discovered that the migration
of the "timerlat/1" thread was performed during thread creation. Further
analysis confirmed that it is because the CPU online processing for
osnoise is implemented through workers, which is asynchronous with the
offline processing. When the worker was scheduled to create a thread, the
CPU may has already been removed from the cpu_online_mask during the offline
process, resulting in the inability to select the right CPU:

T1                       | T2
[CPUHP_ONLINE]           | cpu_device_down()
osnoise_hotplug_workfn() |
                         |     cpus_write_lock()
                         |     takedown_cpu(1)
                         |     cpus_write_unlock()
[CPUHP_OFFLINE]          |
    cpus_read_lock()     |
    start_kthread(1)     |
    cpus_read_unlock()   |

To fix this, skip online processing if the CPU is already offline.

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240924094515.3561410-4-liwei391@huawei.com
Fixes: c8895e271f ("trace/osnoise: Support hotplug operations")
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-03 16:43:22 -04:00
Wei Li
b484a02c9c tracing/timerlat: Drop interface_lock in stop_kthread()
stop_kthread() is the offline callback for "trace/osnoise:online", since
commit 5bfbcd1ee5 ("tracing/timerlat: Add interface_lock around clearing
of kthread in stop_kthread()"), the following ABBA deadlock scenario is
introduced:

T1                            | T2 [BP]               | T3 [AP]
osnoise_hotplug_workfn()      | work_for_cpu_fn()     | cpuhp_thread_fun()
                              |   _cpu_down()         |   osnoise_cpu_die()
  mutex_lock(&interface_lock) |                       |     stop_kthread()
                              |     cpus_write_lock() |       mutex_lock(&interface_lock)
  cpus_read_lock()            |     cpuhp_kick_ap()   |

As the interface_lock here in just for protecting the "kthread" field of
the osn_var, use xchg() instead to fix this issue. Also use
for_each_online_cpu() back in stop_per_cpu_kthreads() as it can take
cpu_read_lock() again.

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240924094515.3561410-3-liwei391@huawei.com
Fixes: 5bfbcd1ee5 ("tracing/timerlat: Add interface_lock around clearing of kthread in stop_kthread()")
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-03 16:43:22 -04:00
Wei Li
0bb0a5c12e tracing/timerlat: Fix duplicated kthread creation due to CPU online/offline
osnoise_hotplug_workfn() is the asynchronous online callback for
"trace/osnoise:online". It may be congested when a CPU goes online and
offline repeatedly and is invoked for multiple times after a certain
online.

This will lead to kthread leak and timer corruption. Add a check
in start_kthread() to prevent this situation.

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240924094515.3561410-2-liwei391@huawei.com
Fixes: c8895e271f ("trace/osnoise: Support hotplug operations")
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-03 16:43:22 -04:00
Steven Rostedt
50a3242d84 tracing: Fix trace_check_vprintf() when tp_printk is used
When the tp_printk kernel command line is used, the trace events go
directly to printk(). It is still checked via the trace_check_vprintf()
function to make sure the pointers of the trace event are legit.

The addition of reading buffers from previous boots required adding a
delta between the addresses of the previous boot and the current boot so
that the pointers in the old buffer can still be used. But this required
adding a trace_array pointer to acquire the delta offsets.

The tp_printk code does not provide a trace_array (tr) pointer, so when
the offsets were examined, a NULL pointer dereference happened and the
kernel crashed.

If the trace_array does not exist, just default the delta offsets to zero,
as that also means the trace event is not being read from a previous boot.

Link: https://lore.kernel.org/all/Zv3z5UsG_jsO9_Tb@aschofie-mobl2.lan/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241003104925.4e1b1fd9@gandalf.local.home
Fixes: 07714b4bb3 ("tracing: Handle old buffer mappings for event strings and functions")
Reported-by: Alison Schofield <alison.schofield@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-03 16:43:22 -04:00
Steven Rostedt
f1f36e22be ftrace: Have calltime be saved in the fgraph storage
The calltime field in the shadow stack frame is only used by the function
graph tracer and profiler. But now that there's other users of the function
graph infrastructure, this adds overhead and wastes space on the shadow
stack. Move the calltime to the fgraph data storage, where the function
graph and profiler entry functions will save it in its own graph storage and
retrieve it in its exit functions.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Link: https://lore.kernel.org/20240914214827.096968730@goodmis.org
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-09-30 11:12:46 -04:00
Steven Rostedt
3c9880f3ab ftrace: Use a running sleeptime instead of saving on shadow stack
The fgraph "sleep-time" option tells the function graph tracer and the
profiler whether to include the time a function "sleeps" (is scheduled off
the CPU) in its duration for the function. By default it is true, which
means the duration of a function is calculated by the timestamp of when the
function was entered to the timestamp of when it exits.

If the "sleep-time" option is disabled, it needs to remove the time that the
task was not running on the CPU during the function. Currently it is done in
a sched_switch tracepoint probe where it moves the "calltime" (time of entry
of the function) forward by the sleep time calculated. It updates all the
calltime in the shadow stack.

This is time consuming for those users of the function graph tracer that
does not care about the sleep time. Instead, add a "ftrace_sleeptime" to the
task_struct that gets the sleep time added each time the task wakes up. Then
have the function entry save the current "ftrace_sleeptime" and on function
exit, move the calltime forward by the difference of the current
"ftrace_sleeptime" from the saved sleeptime.

This removes one dependency of "calltime" needed to be on the shadow stack.
It also simplifies the code that removes the sleep time of functions.

TODO: Only enable the sched_switch tracepoint when this is needed.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Link: https://lore.kernel.org/20240914214826.938908568@goodmis.org
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-09-30 11:12:46 -04:00
Steven Rostedt
a312a0f783 fgraph: Use fgraph data to store subtime for profiler
Instead of having the "subtime" for the function profiler in the
infrastructure ftrace_ret_stack structure, have it use the fgraph data
reserve and retrieve functions.

This will keep the limited shadow stack from wasting 8 bytes for something
that is seldom used.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Link: https://lore.kernel.org/20240914214826.780323141@goodmis.org
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-09-30 11:12:46 -04:00
Masami Hiramatsu (Google)
c54a1a06da tracing: Fix function timing profiler to initialize hashtable
Since the new fgraph requires to initialize fgraph_ops.ops.func_hash before
calling register_ftrace_graph(), initialize it with default (tracing all
functions) parameter.

Cc: stable@vger.kernel.org
Fixes: 5fccc7552c ("ftrace: Add subops logic to allow one ops to manage many")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-09-30 11:12:46 -04:00
Al Viro
cb787f4ac0 [tree-wide] finally take no_llseek out
no_llseek had been defined to NULL two years ago, in commit 868941b144
("fs: remove no_llseek")

To quote that commit,

  At -rc1 we'll need do a mechanical removal of no_llseek -

  git grep -l -w no_llseek | grep -v porting.rst | while read i; do
	sed -i '/\<no_llseek\>/d' $i
  done

  would do it.

Unfortunately, that hadn't been done.  Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
	.llseek = no_llseek,
so it's obviously safe.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-09-27 08:18:43 -07:00
Linus Torvalds
5159938e10 Probes updates for v6.12:
- uprobes: make trace_uprobe->nhit counter a per-CPU one
    This makes uprobe event's hit counter per-CPU for improving
    scalability on multi-core environment.
 
 - kprobes: Remove obsoleted declaration for init_test_probes
    Remove unused init_test_probes() from header.
 
 - Raw tracepoint probe supports raw tracepoint events on modules.
    The tracepoint events using fprobe were introduced in v6.5, but
    tracepoints can be compiled in modules. This supports such a case.
    This includes the following improvements.
   . tracepoint: add a function for iterating over all tracepoints in
     all modules.
   . tracepoint: Add a function for iterating over tracepoints in a
     module.
   . tracing/fprobe: Support raw tracepoint events on modules.
   . tracing/fprobe: Support raw tracepoints on future loaded modules.
      This allows user to add tracepoint events on modules which is
      not loaded yet.
   . selftests/tracing: Add a test for tracepoint events on modules.
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Merge tag 'probes-v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes updates from Masami Hiramatsu:

 - uprobes: make trace_uprobe->nhit counter a per-CPU one

   This makes uprobe event's hit counter per-CPU for improving
   scalability on multi-core environment

 - kprobes: Remove obsoleted declaration for init_test_probes

   Remove unused init_test_probes() from header

 - Raw tracepoint probe supports raw tracepoint events on modules:
     - add a function for iterating over all tracepoints in all modules
     - add a function for iterating over tracepoints in a module
     - support raw tracepoint events on modules
     - support raw tracepoints on future loaded modules
     - add a test for tracepoint events on modules"

* tag 'probes-v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  sefltests/tracing: Add a test for tracepoint events on modules
  tracing/fprobe: Support raw tracepoints on future loaded modules
  tracing/fprobe: Support raw tracepoint events on modules
  tracepoint: Support iterating tracepoints in a loading module
  tracepoint: Support iterating over tracepoints on modules
  kprobes: Remove obsoleted declaration for init_test_probes
  uprobes: turn trace_uprobe's nhit counter to be per-CPU one
2024-09-26 08:55:36 -07:00
Masami Hiramatsu (Google)
57a7e6de9e tracing/fprobe: Support raw tracepoints on future loaded modules
Support raw tracepoint events on future loaded (unloaded) modules.
This allows user to create raw tracepoint events which can be used from
module's __init functions.

Note: since the kernel does not have any information about the tracepoints
in the unloaded modules, fprobe events can not check whether the tracepoint
exists nor extend the BTF based arguments.

Link: https://lore.kernel.org/all/172397780593.286558.18360375226968537828.stgit@devnote2/

Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-09-25 23:23:44 +09:00
Masami Hiramatsu (Google)
67e9a9ee47 tracing/fprobe: Support raw tracepoint events on modules
Support raw tracepoint event on module by fprobe events.
Since it only uses for_each_kernel_tracepoint() to find a tracepoint,
the tracepoints on modules are not handled. Thus if user specified a
tracepoint on a module, it shows an error.
This adds new for_each_module_tracepoint() API to tracepoint subsystem,
and uses it to find tracepoints on modules.

Link: https://lore.kernel.org/all/172397779651.286558.15903703620679186867.stgit@devnote2/

Reported-by: don <zds100@gmail.com>
Closes: https://lore.kernel.org/all/20240530215718.aeec973a1d0bf058d39cb1e3@kernel.org/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-09-25 23:23:44 +09:00
Andrii Nakryiko
10cdb82aa7 uprobes: turn trace_uprobe's nhit counter to be per-CPU one
trace_uprobe->nhit counter is not incremented atomically, so its value
is questionable in when uprobe is hit on multiple CPUs simultaneously.

Also, doing this shared counter increment across many CPUs causes heavy
cache line bouncing, limiting uprobe/uretprobe performance scaling with
number of CPUs.

Solve both problems by making this a per-CPU counter.

Link: https://lore.kernel.org/all/20240813203409.3985398-1-andrii@kernel.org/

Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-09-25 20:10:38 +09:00
Linus Torvalds
af9c191ac2 ring-buffer: Updates for v6.12:
- Merged v6.11-rc3 into trace/ring-buffer/core
 
   The v6.10 ring buffer pull request was not made due to Mathieu Desnoyers
   making a comment to the pull request. Mathieu and I resolved it on IRC,
   but we did not let Linus know that it was resolved. Linus did not do the
   pull thinking it still had some unresolved issues.
 
   The ring buffer work for 6.12 was dependent on both this pull request as
   well as the reserve_mem kernel command line option that was going upstream
   through the memory management tree. The ring buffer repo was being used by
   others so it could not be rebased. In order to continue the work, the
   v6.11-rc3 branch was pulled in to get access to the reserve_mem work.
 
 This has the 6.11 pull request that did not make it into 6.11, which was:
 
   tracing/ring-buffer: Have persistent buffer across reboots
 
   This allows for the tracing instance ring buffer to stay persistent across
   reboots. The way this is done is by adding to the kernel command line:
 
     trace_instance=boot_map@0x285400000:12M
 
   This will reserve 12 megabytes at the address 0x285400000, and then map
   the tracing instance "boot_map" ring buffer to that memory. This will
   appear as a normal instance in the tracefs system:
 
     /sys/kernel/tracing/instances/boot_map
 
   A user could enable tracing in that instance, and on reboot or kernel
   crash, if the memory is not wiped by the firmware, it will recreate the
   trace in that instance. For example, if one was debugging a shutdown of a
   kernel reboot:
 
    # cd /sys/kernel/tracing
    # echo function > instances/boot_map/current_tracer
    # reboot
   [..]
    # cd /sys/kernel/tracing
    # tail instances/boot_map/trace
          swapper/0-1       [000] d..1.   164.549800: restore_boot_irq_mode <-native_machine_shutdown
          swapper/0-1       [000] d..1.   164.549801: native_restore_boot_irq_mode <-native_machine_shutdown
          swapper/0-1       [000] d..1.   164.549802: disconnect_bsp_APIC <-native_machine_shutdown
          swapper/0-1       [000] d..1.   164.549811: hpet_disable <-native_machine_shutdown
          swapper/0-1       [000] d..1.   164.549812: iommu_shutdown_noop <-native_machine_restart
          swapper/0-1       [000] d..1.   164.549813: native_machine_emergency_restart <-__do_sys_reboot
          swapper/0-1       [000] d..1.   164.549813: tboot_shutdown <-native_machine_emergency_restart
          swapper/0-1       [000] d..1.   164.549820: acpi_reboot <-native_machine_emergency_restart
          swapper/0-1       [000] d..1.   164.549821: acpi_reset <-acpi_reboot
          swapper/0-1       [000] d..1.   164.549822: acpi_os_write_port <-acpi_reboot
 
   On reboot, the buffer is examined to make sure it is valid. The validation
   check even steps through every event to make sure the meta data of the
   event is correct. If any test fails, it will simply reset the buffer, and
   the buffer will be empty on boot.
 
 The new changes for 6.12 are:
 
 - Allow the tracing persistent boot buffer to use the "reserve_mem" option
 
   Instead of having the admin find a physical address to store the persistent
   buffer, which can be very tedious if they have to administrate several
   different machines, allow them to use the "reserve_mem" option that will
   find a location for them. It is not as reliable because of KASLR, as the
   loading of the kernel in different locations can cause the memory
   allocated to be inconsistent. Booting with "nokaslr" can make reserve_mem
   more reliable.
 
 - Have function graph tracer handle offsets from a previous boot.
 
   The ring buffer output from a previous boot may have different addresses
   due to kaslr. Have the function graph tracer handle these by using the
   delta from the previous boot to the new boot address space.
 
 - Only reset the saved meta offset when the buffer is started or reset
 
   In the persistent memory meta data, it holds the previous address space
   information, so that it can calculate the delta to have function tracing
   work. But this gets updated after being read to hold the new address
   space. But if the buffer isn't used for that boot, on reboot, the delta is
   now calculated from the previous boot and not the boot that holds the data
   in the ring buffer. This causes the functions not to be shown. Do not save
   the address space information of the current kernel until it is being
   recorded.
 
 - Add a magic variable to test the valid meta data
 
   Add a magic variable in the meta data that can also be used for
   validation. The validator of the previous buffer doesn't need this magic
   data, but it can be used if the meta data is changed by a new kernel, which
   may have the same format that passes the validator but is used
   differently. This magic number can also be used as a "versioning" of the
   meta data.
 
 - Align user space mapped ring buffer sub buffers to improve TLB entries
 
   Linus mentioned that the mapped ring buffer sub buffers were misaligned
   between the meta page and the sub-buffers, so that if the sub-buffers were
   bigger than PAGE_SIZE, it wouldn't allow the TLB to use bigger entries.
 
 - Add new kernel command line "traceoff" to disable tracing on boot for instances
 
   If tracing is enabled for a boot instance, there needs a way to be able to
   disable it on boot so that new events do not get entered into the ring
   buffer and be mixed with events from a previous boot, as that can be
   confusing.
 
 - Allow trace_printk() to go to other instances
 
   Currently, trace_printk() can only go to the top level instance. When
   debugging with a persistent buffer, it is really useful to be able to add
   trace_printk() to go to that buffer, so that you have access to them after
   a crash.
 
 - Do not use "bin_printk()" for traces to a boot instance
 
   The bin_printk() saves only a pointer to the printk format in the ring
   buffer, as the reader of the buffer can still have access to it. But this
   is not the case if the buffer is from a previous boot. If the
   trace_printk() is going to a "persistent" buffer, it will use the slower
   version that writes the printk format into the buffer.
 
 - Add command line option to allow trace_printk() to go to an instance
 
   Allow the kernel command line to define which instance the trace_printk()
   goes to, instead of forcing the admin to set it for every boot via the
   tracefs options.
 
 - Start a document that explains how to use tracefs to debug the kernel
 
 - Add some more kernel selftests to test user mapped ring buffer
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Merge tag 'trace-ring-buffer-v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ring-buffer updates from Steven Rostedt:

 - tracing/ring-buffer: persistent buffer across reboots

   This allows for the tracing instance ring buffer to stay persistent
   across reboots. The way this is done is by adding to the kernel
   command line:

     trace_instance=boot_map@0x285400000:12M

   This will reserve 12 megabytes at the address 0x285400000, and then
   map the tracing instance "boot_map" ring buffer to that memory. This
   will appear as a normal instance in the tracefs system:

     /sys/kernel/tracing/instances/boot_map

   A user could enable tracing in that instance, and on reboot or kernel
   crash, if the memory is not wiped by the firmware, it will recreate
   the trace in that instance. For example, if one was debugging a
   shutdown of a kernel reboot:

     # cd /sys/kernel/tracing
     # echo function > instances/boot_map/current_tracer
     # reboot
     [..]
     # cd /sys/kernel/tracing
     # tail instances/boot_map/trace
           swapper/0-1       [000] d..1.   164.549800: restore_boot_irq_mode <-native_machine_shutdown
           swapper/0-1       [000] d..1.   164.549801: native_restore_boot_irq_mode <-native_machine_shutdown
           swapper/0-1       [000] d..1.   164.549802: disconnect_bsp_APIC <-native_machine_shutdown
           swapper/0-1       [000] d..1.   164.549811: hpet_disable <-native_machine_shutdown
           swapper/0-1       [000] d..1.   164.549812: iommu_shutdown_noop <-native_machine_restart
           swapper/0-1       [000] d..1.   164.549813: native_machine_emergency_restart <-__do_sys_reboot
           swapper/0-1       [000] d..1.   164.549813: tboot_shutdown <-native_machine_emergency_restart
           swapper/0-1       [000] d..1.   164.549820: acpi_reboot <-native_machine_emergency_restart
           swapper/0-1       [000] d..1.   164.549821: acpi_reset <-acpi_reboot
           swapper/0-1       [000] d..1.   164.549822: acpi_os_write_port <-acpi_reboot

   On reboot, the buffer is examined to make sure it is valid. The
   validation check even steps through every event to make sure the meta
   data of the event is correct. If any test fails, it will simply reset
   the buffer, and the buffer will be empty on boot.

 - Allow the tracing persistent boot buffer to use the "reserve_mem"
   option

   Instead of having the admin find a physical address to store the
   persistent buffer, which can be very tedious if they have to
   administrate several different machines, allow them to use the
   "reserve_mem" option that will find a location for them. It is not as
   reliable because of KASLR, as the loading of the kernel in different
   locations can cause the memory allocated to be inconsistent. Booting
   with "nokaslr" can make reserve_mem more reliable.

 - Have function graph tracer handle offsets from a previous boot.

   The ring buffer output from a previous boot may have different
   addresses due to kaslr. Have the function graph tracer handle these
   by using the delta from the previous boot to the new boot address
   space.

 - Only reset the saved meta offset when the buffer is started or reset

   In the persistent memory meta data, it holds the previous address
   space information, so that it can calculate the delta to have
   function tracing work. But this gets updated after being read to hold
   the new address space. But if the buffer isn't used for that boot, on
   reboot, the delta is now calculated from the previous boot and not
   the boot that holds the data in the ring buffer. This causes the
   functions not to be shown. Do not save the address space information
   of the current kernel until it is being recorded.

 - Add a magic variable to test the valid meta data

   Add a magic variable in the meta data that can also be used for
   validation. The validator of the previous buffer doesn't need this
   magic data, but it can be used if the meta data is changed by a new
   kernel, which may have the same format that passes the validator but
   is used differently. This magic number can also be used as a
   "versioning" of the meta data.

 - Align user space mapped ring buffer sub buffers to improve TLB
   entries

   Linus mentioned that the mapped ring buffer sub buffers were
   misaligned between the meta page and the sub-buffers, so that if the
   sub-buffers were bigger than PAGE_SIZE, it wouldn't allow the TLB to
   use bigger entries.

 - Add new kernel command line "traceoff" to disable tracing on boot for
   instances

   If tracing is enabled for a boot instance, there needs a way to be
   able to disable it on boot so that new events do not get entered into
   the ring buffer and be mixed with events from a previous boot, as
   that can be confusing.

 - Allow trace_printk() to go to other instances

   Currently, trace_printk() can only go to the top level instance. When
   debugging with a persistent buffer, it is really useful to be able to
   add trace_printk() to go to that buffer, so that you have access to
   them after a crash.

 - Do not use "bin_printk()" for traces to a boot instance

   The bin_printk() saves only a pointer to the printk format in the
   ring buffer, as the reader of the buffer can still have access to it.
   But this is not the case if the buffer is from a previous boot. If
   the trace_printk() is going to a "persistent" buffer, it will use the
   slower version that writes the printk format into the buffer.

 - Add command line option to allow trace_printk() to go to an instance

   Allow the kernel command line to define which instance the
   trace_printk() goes to, instead of forcing the admin to set it for
   every boot via the tracefs options.

 - Start a document that explains how to use tracefs to debug the kernel

 - Add some more kernel selftests to test user mapped ring buffer

* tag 'trace-ring-buffer-v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (28 commits)
  selftests/ring-buffer: Handle meta-page bigger than the system
  selftests/ring-buffer: Verify the entire meta-page padding
  tracing/Documentation: Start a document on how to debug with tracing
  tracing: Add option to set an instance to be the trace_printk destination
  tracing: Have trace_printk not use binary prints if boot buffer
  tracing: Allow trace_printk() to go to other instance buffers
  tracing: Add "traceoff" flag to boot time tracing instances
  ring-buffer: Align meta-page to sub-buffers for improved TLB usage
  ring-buffer: Add magic and struct size to boot up meta data
  ring-buffer: Don't reset persistent ring-buffer meta saved addresses
  tracing/fgraph: Have fgraph handle previous boot function addresses
  tracing: Allow boot instances to use reserve_mem boot memory
  tracing: Fix ifdef of snapshots to not prevent last_boot_info file
  ring-buffer: Use vma_pages() helper function
  tracing: Fix NULL vs IS_ERR() check in enable_instances()
  tracing: Add last boot delta offset for stack traces
  tracing: Update function tracing output for previous boot buffer
  tracing: Handle old buffer mappings for event strings and functions
  tracing/ring-buffer: Add last_boot_info file to boot instance
  ring-buffer: Save text and data locations in mapped meta data
  ...
2024-09-22 09:47:16 -07:00
Linus Torvalds
440b652328 bpf-next-6.12
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Merge tag 'bpf-next-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Pull bpf updates from Alexei Starovoitov:

 - Introduce '__attribute__((bpf_fastcall))' for helpers and kfuncs with
   corresponding support in LLVM.

   It is similar to existing 'no_caller_saved_registers' attribute in
   GCC/LLVM with a provision for backward compatibility. It allows
   compilers generate more efficient BPF code assuming the verifier or
   JITs will inline or partially inline a helper/kfunc with such
   attribute. bpf_cast_to_kern_ctx, bpf_rdonly_cast,
   bpf_get_smp_processor_id are the first set of such helpers.

 - Harden and extend ELF build ID parsing logic.

   When called from sleepable context the relevants parts of ELF file
   will be read to find and fetch .note.gnu.build-id information. Also
   harden the logic to avoid TOCTOU, overflow, out-of-bounds problems.

 - Improvements and fixes for sched-ext:
    - Allow passing BPF iterators as kfunc arguments
    - Make the pointer returned from iter_next method trusted
    - Fix x86 JIT convergence issue due to growing/shrinking conditional
      jumps in variable length encoding

 - BPF_LSM related:
    - Introduce few VFS kfuncs and consolidate them in
      fs/bpf_fs_kfuncs.c
    - Enforce correct range of return values from certain LSM hooks
    - Disallow attaching to other LSM hooks

 - Prerequisite work for upcoming Qdisc in BPF:
    - Allow kptrs in program provided structs
    - Support for gen_epilogue in verifier_ops

 - Important fixes:
    - Fix uprobe multi pid filter check
    - Fix bpf_strtol and bpf_strtoul helpers
    - Track equal scalars history on per-instruction level
    - Fix tailcall hierarchy on x86 and arm64
    - Fix signed division overflow to prevent INT_MIN/-1 trap on x86
    - Fix get kernel stack in BPF progs attached to tracepoint:syscall

 - Selftests:
    - Add uprobe bench/stress tool
    - Generate file dependencies to drastically improve re-build time
    - Match JIT-ed and BPF asm with __xlated/__jited keywords
    - Convert older tests to test_progs framework
    - Add support for RISC-V
    - Few fixes when BPF programs are compiled with GCC-BPF backend
      (support for GCC-BPF in BPF CI is ongoing in parallel)
    - Add traffic monitor
    - Enable cross compile and musl libc

* tag 'bpf-next-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (260 commits)
  btf: require pahole 1.21+ for DEBUG_INFO_BTF with default DWARF version
  btf: move pahole check in scripts/link-vmlinux.sh to lib/Kconfig.debug
  btf: remove redundant CONFIG_BPF test in scripts/link-vmlinux.sh
  bpf: Call the missed kfree() when there is no special field in btf
  bpf: Call the missed btf_record_free() when map creation fails
  selftests/bpf: Add a test case to write mtu result into .rodata
  selftests/bpf: Add a test case to write strtol result into .rodata
  selftests/bpf: Rename ARG_PTR_TO_LONG test description
  selftests/bpf: Fix ARG_PTR_TO_LONG {half-,}uninitialized test
  bpf: Zero former ARG_PTR_TO_{LONG,INT} args in case of error
  bpf: Improve check_raw_mode_ok test for MEM_UNINIT-tagged types
  bpf: Fix helper writes to read-only maps
  bpf: Remove truncation test in bpf_strtol and bpf_strtoul helpers
  bpf: Fix bpf_strtol and bpf_strtoul helpers for 32bit
  selftests/bpf: Add tests for sdiv/smod overflow cases
  bpf: Fix a sdiv overflow issue
  libbpf: Add bpf_object__token_fd accessor
  docs/bpf: Add missing BPF program types to docs
  docs/bpf: Add constant values for linkages
  bpf: Use fake pt_regs when doing bpf syscall tracepoint tracing
  ...
2024-09-21 09:27:50 -07:00
Linus Torvalds
2004cef11e In the v6.12 scheduler development cycle we had 63 commits from 18 contributors:
- Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot de Oliveira's
    last major contribution to the kernel:
 
      "SCHED_DEADLINE servers can help fixing starvation issues of low priority
      tasks (e.g., SCHED_OTHER) when higher priority tasks monopolize CPU
      cycles. Today we have RT Throttling; DEADLINE servers should be able to
      replace and improve that."
 
      (Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes,
       Youssef Esmat, Huang Shijie)
 
  - Preparatory changes for sched_ext integration:
 
      - Use set_next_task(.first) where required
      - Fix up set_next_task() implementations
      - Clean up DL server vs. core sched
      - Split up put_prev_task_balance()
      - Rework pick_next_task()
      - Combine the last put_prev_task() and the first set_next_task()
      - Rework dl_server
      - Add put_prev_task(.next)
 
       (Peter Zijlstra, with a fix by Tejun Heo)
 
  - Complete the EEVDF transition and refine EEVDF scheduling:
 
      - Implement delayed dequeue
      - Allow shorter slices to wakeup-preempt
      - Use sched_attr::sched_runtime to set request/slice suggestion
      - Document the new feature flags
      - Remove unused and duplicate-functionality fields
      - Simplify & unify pick_next_task_fair()
      - Misc debuggability enhancements
 
       (Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann,
        Valentin Schneider and Chuyi Zhou)
 
  - Initialize the vruntime of a new task when it is first enqueued,
    resulting in significant decrease in latency of newly woken tasks.
    (Zhang Qiao)
 
  - Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
    (K Prateek Nayak, Peter Zijlstra)
 
  - Clean up and clarify the usage of Clean up usage of rt_task()
    (Qais Yousef)
 
  - Preempt SCHED_IDLE entities in strict cgroup hierarchies
    (Tianchen Ding)
 
  - Clarify the documentation of time units for deadline scheduler
    parameters. (Christian Loehle)
 
  - Remove the HZ_BW chicken-bit feature flag introduced a year ago,
    the original change seems to be working fine.
    (Phil Auld)
 
  - Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
    Peilin He, Qais Yousefm and Vincent Guittot)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot
   de Oliveira's last major contribution to the kernel:

     "SCHED_DEADLINE servers can help fixing starvation issues of low
      priority tasks (e.g., SCHED_OTHER) when higher priority tasks
      monopolize CPU cycles. Today we have RT Throttling; DEADLINE
      servers should be able to replace and improve that."

   (Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes, Youssef
   Esmat, Huang Shijie)

 - Preparatory changes for sched_ext integration:
     - Use set_next_task(.first) where required
     - Fix up set_next_task() implementations
     - Clean up DL server vs. core sched
     - Split up put_prev_task_balance()
     - Rework pick_next_task()
     - Combine the last put_prev_task() and the first set_next_task()
     - Rework dl_server
     - Add put_prev_task(.next)

   (Peter Zijlstra, with a fix by Tejun Heo)

 - Complete the EEVDF transition and refine EEVDF scheduling:
     - Implement delayed dequeue
     - Allow shorter slices to wakeup-preempt
     - Use sched_attr::sched_runtime to set request/slice suggestion
     - Document the new feature flags
     - Remove unused and duplicate-functionality fields
     - Simplify & unify pick_next_task_fair()
     - Misc debuggability enhancements

   (Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann, Valentin
   Schneider and Chuyi Zhou)

 - Initialize the vruntime of a new task when it is first enqueued,
   resulting in significant decrease in latency of newly woken tasks
   (Zhang Qiao)

 - Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
   (K Prateek Nayak, Peter Zijlstra)

 - Clean up and clarify the usage of Clean up usage of rt_task()
   (Qais Yousef)

 - Preempt SCHED_IDLE entities in strict cgroup hierarchies
   (Tianchen Ding)

 - Clarify the documentation of time units for deadline scheduler
   parameters (Christian Loehle)

 - Remove the HZ_BW chicken-bit feature flag introduced a year ago,
   the original change seems to be working fine (Phil Auld)

 - Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
   Peilin He, Qais Yousefm and Vincent Guittot)

* tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
  sched/cpufreq: Use NSEC_PER_MSEC for deadline task
  cpufreq/cppc: Use NSEC_PER_MSEC for deadline task
  sched/deadline: Clarify nanoseconds in uapi
  sched/deadline: Convert schedtool example to chrt
  sched/debug: Fix the runnable tasks output
  sched: Fix sched_delayed vs sched_core
  kernel/sched: Fix util_est accounting for DELAY_DEQUEUE
  kthread: Fix task state in kthread worker if being frozen
  sched/pelt: Use rq_clock_task() for hw_pressure
  sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c
  sched/core: Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
  sched: Add put_prev_task(.next)
  sched: Rework dl_server
  sched: Combine the last put_prev_task() and the first set_next_task()
  sched: Rework pick_next_task()
  sched: Split up put_prev_task_balance()
  sched: Clean up DL server vs core sched
  sched: Fixup set_next_task() implementations
  sched: Use set_next_task(.first) where required
  sched/fair: Properly deactivate sched_delayed task upon class change
  ...
2024-09-19 15:55:58 +02:00
Linus Torvalds
9f0c253ddd Performance events changes for v6.12:
- Implement per-PMU context rescheduling to significantly improve single-PMU
    performance, and related cleanups/fixes. (by Peter Zijlstra and Namhyung Kim)
 
  - Fix ancient bug resulting in a lot of events being dropped erroneously
    at higher sampling frequencies. (by Luo Gengkun)
 
  - uprobes enhancements:
 
      - Implement RCU-protected hot path optimizations for better performance:
 
          "For baseline vs SRCU, peak througput increased from 3.7 M/s (million uprobe
           triggerings per second) up to about 8 M/s. For uretprobes it's a bit more
           modest with bump from 2.4 M/s to 5 M/s.
 
           For SRCU vs RCU Tasks Trace, peak throughput for uprobes increases further from
           8 M/s to 10.3 M/s (+28%!), and for uretprobes from 5.3 M/s to 5.8 M/s (+11%),
           as we have more work to do on uretprobes side.
 
           Even single-thread (no contention) performance is slightly better: 3.276 M/s to
           3.396 M/s (+3.5%) for uprobes, and 2.055 M/s to 2.174 M/s (+5.8%)
           for uretprobes."
 
           (by Andrii Nakryiko et al)
 
      - Document mmap_lock, don't abuse get_user_pages_remote(). (by Oleg Nesterov)
 
      - Cleanups & fixes to prepare for future work:
 
         - Remove uprobe_register_refctr()
 	- Simplify error handling for alloc_uprobe()
         - Make uprobe_register() return struct uprobe *
         - Fold __uprobe_unregister() into uprobe_unregister()
         - Shift put_uprobe() from delete_uprobe() to uprobe_unregister()
         - BPF: Fix use-after-free in bpf_uprobe_multi_link_attach()
 
           (by Oleg Nesterov)
 
  - New feature & ABI extension: allow events to use PERF_SAMPLE READ with
    inheritance, enabling sample based profiling of a group of counters over
    a hierarchy of processes or threads.  (by Ben Gainey)
 
  - Intel uncore & power events updates:
 
       - Add Arrow Lake and Lunar Lake support
       - Add PERF_EV_CAP_READ_SCOPE
       - Clean up and enhance cpumask and hotplug support
 
         (by Kan Liang)
 
       - Add LNL uncore iMC freerunning support
       - Use D0:F0 as a default device
 
         (by Zhenyu Wang)
 
  - Intel PT: fix AUX snapshot handling race. (by Adrian Hunter)
 
  - Misc fixes and cleanups. (by James Clark, Jiri Olsa, Oleg Nesterov and Peter Zijlstra)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-core-2024-09-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf events updates from Ingo Molnar:

 - Implement per-PMU context rescheduling to significantly improve
   single-PMU performance, and related cleanups/fixes (Peter Zijlstra
   and Namhyung Kim)

 - Fix ancient bug resulting in a lot of events being dropped
   erroneously at higher sampling frequencies (Luo Gengkun)

 - uprobes enhancements:

     - Implement RCU-protected hot path optimizations for better
       performance:

         "For baseline vs SRCU, peak througput increased from 3.7 M/s
          (million uprobe triggerings per second) up to about 8 M/s. For
          uretprobes it's a bit more modest with bump from 2.4 M/s to
          5 M/s.

          For SRCU vs RCU Tasks Trace, peak throughput for uprobes
          increases further from 8 M/s to 10.3 M/s (+28%!), and for
          uretprobes from 5.3 M/s to 5.8 M/s (+11%), as we have more
          work to do on uretprobes side.

          Even single-thread (no contention) performance is slightly
          better: 3.276 M/s to 3.396 M/s (+3.5%) for uprobes, and 2.055
          M/s to 2.174 M/s (+5.8%) for uretprobes."

          (Andrii Nakryiko et al)

     - Document mmap_lock, don't abuse get_user_pages_remote() (Oleg
       Nesterov)

     - Cleanups & fixes to prepare for future work:
        - Remove uprobe_register_refctr()
	- Simplify error handling for alloc_uprobe()
        - Make uprobe_register() return struct uprobe *
        - Fold __uprobe_unregister() into uprobe_unregister()
        - Shift put_uprobe() from delete_uprobe() to uprobe_unregister()
        - BPF: Fix use-after-free in bpf_uprobe_multi_link_attach()
          (Oleg Nesterov)

 - New feature & ABI extension: allow events to use PERF_SAMPLE READ
   with inheritance, enabling sample based profiling of a group of
   counters over a hierarchy of processes or threads (Ben Gainey)

 - Intel uncore & power events updates:

      - Add Arrow Lake and Lunar Lake support
      - Add PERF_EV_CAP_READ_SCOPE
      - Clean up and enhance cpumask and hotplug support
        (Kan Liang)

      - Add LNL uncore iMC freerunning support
      - Use D0:F0 as a default device
        (Zhenyu Wang)

 - Intel PT: fix AUX snapshot handling race (Adrian Hunter)

 - Misc fixes and cleanups (James Clark, Jiri Olsa, Oleg Nesterov and
   Peter Zijlstra)

* tag 'perf-core-2024-09-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits)
  dmaengine: idxd: Clean up cpumask and hotplug for perfmon
  iommu/vt-d: Clean up cpumask and hotplug for perfmon
  perf/x86/intel/cstate: Clean up cpumask and hotplug
  perf: Add PERF_EV_CAP_READ_SCOPE
  perf: Generic hotplug support for a PMU with a scope
  uprobes: perform lockless SRCU-protected uprobes_tree lookup
  rbtree: provide rb_find_rcu() / rb_find_add_rcu()
  perf/uprobe: split uprobe_unregister()
  uprobes: travers uprobe's consumer list locklessly under SRCU protection
  uprobes: get rid of enum uprobe_filter_ctx in uprobe filter callbacks
  uprobes: protected uprobe lifetime with SRCU
  uprobes: revamp uprobe refcounting and lifetime management
  bpf: Fix use-after-free in bpf_uprobe_multi_link_attach()
  perf/core: Fix small negative period being ignored
  perf: Really fix event_function_call() locking
  perf: Optimize __pmu_ctx_sched_out()
  perf: Add context time freeze
  perf: Fix event_function_call() locking
  perf: Extract a few helpers
  perf: Optimize context reschedule for single PMU cases
  ...
2024-09-18 15:03:58 +02:00
Linus Torvalds
067610ebaa RCU pull request for v6.12
This pull request contains the following branches:
 
 context_tracking.15.08.24a: Rename context tracking state related
         symbols and remove references to "dynticks" in various context
         tracking state variables and related helpers; force
         context_tracking_enabled_this_cpu() to be inlined to avoid
         leaving a noinstr section.
 
 csd.lock.15.08.24a: Enhance CSD-lock diagnostic reports; add an API
         to provide an indication of ongoing CSD-lock stall.
 
 nocb.09.09.24a: Update and simplify RCU nocb code to handle
         (de-)offloading of callbacks only for offline CPUs; fix RT
         throttling hrtimer being armed from offline CPU.
 
 rcutorture.14.08.24a: Remove redundant rcu_torture_ops get_gp_completed
         fields; add SRCU ->same_gp_state and ->get_comp_state
         functions; add generic test for NUM_ACTIVE_*RCU_POLL* for
         testing RCU and SRCU polled grace periods; add CFcommon.arch
         for arch-specific Kconfig options; print number of update types
         in rcu_torture_write_types();
         add rcutree.nohz_full_patience_delay testing to the TREE07
         scenario; add a stall_cpu_repeat module parameter to test
         repeated CPU stalls; add argument to limit number of CPUs a
         guest OS can use in torture.sh;
 
 rcustall.09.09.24a: Abbreviate RCU CPU stall warnings during CSD-lock
         stalls; Allow dump_cpu_task() to be called without disabling
         preemption; defer printing stall-warning backtrace when holding
         rcu_node lock.
 
 srcu.12.08.24a: Make SRCU gp seq wrap-around faster; add KCSAN checks
         for concurrent updates to ->srcu_n_exp_nodelay and
         ->reschedule_count which are used in heuristics governing
         auto-expediting of normal SRCU grace periods and
         grace-period-state-machine delays; mark idle SRCU-barrier
         callbacks to help identify stuck SRCU-barrier callback.
 
 rcu.tasks.14.08.24a: Remove RCU Tasks Rude asynchronous APIs as they
         are no longer used; stop testing RCU Tasks Rude asynchronous
         APIs; fix access to non-existent percpu regions; check
         processor-ID assumptions during chosen CPU calculation for
         callback enqueuing; update description of rtp->tasks_gp_seq
         grace-period sequence number; add rcu_barrier_cb_is_done()
         to identify whether a given rcu_barrier callback is stuck;
         mark idle Tasks-RCU-barrier callbacks; add
         *torture_stats_print() functions to print detailed
         diagnostics for Tasks-RCU variants; capture start time of
         rcu_barrier_tasks*() operation to help distinguish a hung
         barrier operation from a long series of barrier operations.
 
 rcu_scaling_tests.15.08.24a:
         refscale: Add a TINY scenario to support tests of Tiny RCU
         and Tiny SRCU; Optimize process_durations() operation;
 
         rcuscale: Dump stacks of stalled rcu_scale_writer() instances;
         dump grace-period statistics when rcu_scale_writer() stalls;
         mark idle RCU-barrier callbacks to identify stuck RCU-barrier
         callbacks; print detailed grace-period and barrier diagnostics
         on rcu_scale_writer() hangs for Tasks-RCU variants; warn if
         async module parameter is specified for RCU implementations
         that do not have async primitives such as RCU Tasks Rude;
         make all writer tasks report upon hang; tolerate repeated
         GFP_KERNEL failure in rcu_scale_writer(); use special allocator
         for rcu_scale_writer(); NULL out top-level pointers to heap
         memory to avoid double-free bugs on modprobe failures; maintain
         per-task instead of per-CPU callbacks count to avoid any issues
         with migration of either tasks or callbacks; constify struct
         ref_scale_ops.
 
 fixes.12.08.24a: Use system_unbound_wq for kfree_rcu work to avoid
         disturbing isolated CPUs.
 
 misc.11.08.24a: Warn on unexpected rcu_state.srs_done_tail state;
         Better define "atomic" for list_replace_rcu() and
         hlist_replace_rcu() routines; annotate struct
         kvfree_rcu_bulk_data with __counted_by().
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Merge tag 'rcu.release.v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux

Pull RCU updates from Neeraj Upadhyay:
 "Context tracking:
   - rename context tracking state related symbols and remove references
     to "dynticks" in various context tracking state variables and
     related helpers
   - force context_tracking_enabled_this_cpu() to be inlined to avoid
     leaving a noinstr section

  CSD lock:
   - enhance CSD-lock diagnostic reports
   - add an API to provide an indication of ongoing CSD-lock stall

  nocb:
   - update and simplify RCU nocb code to handle (de-)offloading of
     callbacks only for offline CPUs
   - fix RT throttling hrtimer being armed from offline CPU

  rcutorture:
   - remove redundant rcu_torture_ops get_gp_completed fields
   - add SRCU ->same_gp_state and ->get_comp_state functions
   - add generic test for NUM_ACTIVE_*RCU_POLL* for testing RCU and SRCU
     polled grace periods
   - add CFcommon.arch for arch-specific Kconfig options
   - print number of update types in rcu_torture_write_types()
   - add rcutree.nohz_full_patience_delay testing to the TREE07 scenario
   - add a stall_cpu_repeat module parameter to test repeated CPU stalls
   - add argument to limit number of CPUs a guest OS can use in
     torture.sh

  rcustall:
   - abbreviate RCU CPU stall warnings during CSD-lock stalls
   - Allow dump_cpu_task() to be called without disabling preemption
   - defer printing stall-warning backtrace when holding rcu_node lock

  srcu:
   - make SRCU gp seq wrap-around faster
   - add KCSAN checks for concurrent updates to ->srcu_n_exp_nodelay and
     ->reschedule_count which are used in heuristics governing
     auto-expediting of normal SRCU grace periods and
     grace-period-state-machine delays
   - mark idle SRCU-barrier callbacks to help identify stuck
     SRCU-barrier callback

  rcu tasks:
   - remove RCU Tasks Rude asynchronous APIs as they are no longer used
   - stop testing RCU Tasks Rude asynchronous APIs
   - fix access to non-existent percpu regions
   - check processor-ID assumptions during chosen CPU calculation for
     callback enqueuing
   - update description of rtp->tasks_gp_seq grace-period sequence
     number
   - add rcu_barrier_cb_is_done() to identify whether a given
     rcu_barrier callback is stuck
   - mark idle Tasks-RCU-barrier callbacks
   - add *torture_stats_print() functions to print detailed diagnostics
     for Tasks-RCU variants
   - capture start time of rcu_barrier_tasks*() operation to help
     distinguish a hung barrier operation from a long series of barrier
     operations

  refscale:
   - add a TINY scenario to support tests of Tiny RCU and Tiny
     SRCU
   - optimize process_durations() operation

  rcuscale:
   - dump stacks of stalled rcu_scale_writer() instances and
     grace-period statistics when rcu_scale_writer() stalls
   - mark idle RCU-barrier callbacks to identify stuck RCU-barrier
     callbacks
   - print detailed grace-period and barrier diagnostics on
     rcu_scale_writer() hangs for Tasks-RCU variants
   - warn if async module parameter is specified for RCU implementations
     that do not have async primitives such as RCU Tasks Rude
   - make all writer tasks report upon hang
   - tolerate repeated GFP_KERNEL failure in rcu_scale_writer()
   - use special allocator for rcu_scale_writer()
   - NULL out top-level pointers to heap memory to avoid double-free
     bugs on modprobe failures
   - maintain per-task instead of per-CPU callbacks count to avoid any
     issues with migration of either tasks or callbacks
   - constify struct ref_scale_ops

  Fixes:
   - use system_unbound_wq for kfree_rcu work to avoid disturbing
     isolated CPUs

  Misc:
   - warn on unexpected rcu_state.srs_done_tail state
   - better define "atomic" for list_replace_rcu() and
     hlist_replace_rcu() routines
   - annotate struct kvfree_rcu_bulk_data with __counted_by()"

* tag 'rcu.release.v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (90 commits)
  rcu: Defer printing stall-warning backtrace when holding rcu_node lock
  rcu/nocb: Remove superfluous memory barrier after bypass enqueue
  rcu/nocb: Conditionally wake up rcuo if not already waiting on GP
  rcu/nocb: Fix RT throttling hrtimer armed from offline CPU
  rcu/nocb: Simplify (de-)offloading state machine
  context_tracking: Tag context_tracking_enabled_this_cpu() __always_inline
  context_tracking, rcu: Rename rcu_dyntick trace event into rcu_watching
  rcu: Update stray documentation references to rcu_dynticks_eqs_{enter, exit}()
  rcu: Rename rcu_momentary_dyntick_idle() into rcu_momentary_eqs()
  rcu: Rename rcu_implicit_dynticks_qs() into rcu_watching_snap_recheck()
  rcu: Rename dyntick_save_progress_counter() into rcu_watching_snap_save()
  rcu: Rename struct rcu_data .exp_dynticks_snap into .exp_watching_snap
  rcu: Rename struct rcu_data .dynticks_snap into .watching_snap
  rcu: Rename rcu_dynticks_zero_in_eqs() into rcu_watching_zero_in_eqs()
  rcu: Rename rcu_dynticks_in_eqs_since() into rcu_watching_snap_stopped_since()
  rcu: Rename rcu_dynticks_in_eqs() into rcu_watching_snap_in_eqs()
  rcu: Rename rcu_dynticks_eqs_online() into rcu_watching_online()
  context_tracking, rcu: Rename rcu_dynticks_curr_cpu_in_eqs() into rcu_is_watching_curr_cpu()
  context_tracking, rcu: Rename rcu_dynticks_task*() into rcu_task*()
  refscale: Constify struct ref_scale_ops
  ...
2024-09-18 07:52:24 +02:00
Daniel Borkmann
32556ce93b bpf: Fix helper writes to read-only maps
Lonial found an issue that despite user- and BPF-side frozen BPF map
(like in case of .rodata), it was still possible to write into it from
a BPF program side through specific helpers having ARG_PTR_TO_{LONG,INT}
as arguments.

In check_func_arg() when the argument is as mentioned, the meta->raw_mode
is never set. Later, check_helper_mem_access(), under the case of
PTR_TO_MAP_VALUE as register base type, it assumes BPF_READ for the
subsequent call to check_map_access_type() and given the BPF map is
read-only it succeeds.

The helpers really need to be annotated as ARG_PTR_TO_{LONG,INT} | MEM_UNINIT
when results are written into them as opposed to read out of them. The
latter indicates that it's okay to pass a pointer to uninitialized memory
as the memory is written to anyway.

However, ARG_PTR_TO_{LONG,INT} is a special case of ARG_PTR_TO_FIXED_SIZE_MEM
just with additional alignment requirement. So it is better to just get
rid of the ARG_PTR_TO_{LONG,INT} special cases altogether and reuse the
fixed size memory types. For this, add MEM_ALIGNED to additionally ensure
alignment given these helpers write directly into the args via *<ptr> = val.
The .arg*_size has been initialized reflecting the actual sizeof(*<ptr>).

MEM_ALIGNED can only be used in combination with MEM_FIXED_SIZE annotated
argument types, since in !MEM_FIXED_SIZE cases the verifier does not know
the buffer size a priori and therefore cannot blindly write *<ptr> = val.

Fixes: 57c3bb725a ("bpf: Introduce ARG_PTR_TO_{INT,LONG} arg types")
Reported-by: Lonial Con <kongln9170@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Link: https://lore.kernel.org/r/20240913191754.13290-3-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-09-13 13:17:55 -07:00
Yonghong Song
376bd59e2a bpf: Use fake pt_regs when doing bpf syscall tracepoint tracing
Salvatore Benedetto reported an issue that when doing syscall tracepoint
tracing the kernel stack is empty. For example, using the following
command line
  bpftrace -e 'tracepoint:syscalls:sys_enter_read { print("Kernel Stack\n"); print(kstack()); }'
  bpftrace -e 'tracepoint:syscalls:sys_exit_read { print("Kernel Stack\n"); print(kstack()); }'
the output for both commands is
===
  Kernel Stack
===

Further analysis shows that pt_regs used for bpf syscall tracepoint
tracing is from the one constructed during user->kernel transition.
The call stack looks like
  perf_syscall_enter+0x88/0x7c0
  trace_sys_enter+0x41/0x80
  syscall_trace_enter+0x100/0x160
  do_syscall_64+0x38/0xf0
  entry_SYSCALL_64_after_hwframe+0x76/0x7e

The ip address stored in pt_regs is from user space hence no kernel
stack is printed.

To fix the issue, kernel address from pt_regs is required.
In kernel repo, there are already a few cases like this. For example,
in kernel/trace/bpf_trace.c, several perf_fetch_caller_regs(fake_regs_ptr)
instances are used to supply ip address or use ip address to construct
call stack.

Instead of allocate fake_regs in the stack which may consume
a lot of bytes, the function perf_trace_buf_alloc() in
perf_syscall_{enter, exit}() is leveraged to create fake_regs,
which will be passed to perf_call_bpf_{enter,exit}().

For the above bpftrace script, I got the following output with this patch:
for tracepoint:syscalls:sys_enter_read
===
  Kernel Stack

        syscall_trace_enter+407
        syscall_trace_enter+407
        do_syscall_64+74
        entry_SYSCALL_64_after_hwframe+75
===
and for tracepoint:syscalls:sys_exit_read
===
Kernel Stack

        syscall_exit_work+185
        syscall_exit_work+185
        syscall_exit_to_user_mode+305
        do_syscall_64+118
        entry_SYSCALL_64_after_hwframe+75
===

Reported-by: Salvatore Benedetto <salvabenedetto@meta.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240910214037.3663272-1-yonghong.song@linux.dev
2024-09-11 13:27:27 -07:00
Andrii Nakryiko
d4dd9775ec bpf: wire up sleepable bpf_get_stack() and bpf_get_task_stack() helpers
Add sleepable implementations of bpf_get_stack() and
bpf_get_task_stack() helpers and allow them to be used from sleepable
BPF program (e.g., sleepable uprobes).

Note, the stack trace IPs capturing itself is not sleepable (that would
need to be a separate project), only build ID fetching is sleepable and
thus more reliable, as it will wait for data to be paged in, if
necessary. For that we make use of sleepable build_id_parse()
implementation.

Now that build ID related internals in kernel/bpf/stackmap.c can be used
both in sleepable and non-sleepable contexts, we need to add additional
rcu_read_lock()/rcu_read_unlock() protection around fetching
perf_callchain_entry, but with the refactoring in previous commit it's
now pretty straightforward. We make sure to do rcu_read_unlock (in
sleepable mode only) right before stack_map_get_build_id_offset() call
which can sleep. By that time we don't have any more use of
perf_callchain_entry.

Note, bpf_get_task_stack() will fail for user mode if task != current.
And for kernel mode build ID are irrelevant. So in that sense adding
sleepable bpf_get_task_stack() implementation is a no-op. It feel right
to wire this up for symmetry and completeness, but I'm open to just
dropping it until we support `user && crosstask` condition.

Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-10-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-09-11 09:58:31 -07:00
Andy Shevchenko
4e378158e5 tracing: Drop unused helper function to fix the build
A helper function defined but not used. This, in particular,
prevents kernel builds with clang, `make W=1` and CONFIG_WERROR=y:

kernel/trace/trace.c:2229:19: error: unused function 'run_tracer_selftest' [-Werror,-Wunused-function]
 2229 | static inline int run_tracer_selftest(struct tracer *type)
      |                   ^~~~~~~~~~~~~~~~~~~

Fix this by dropping unused functions.

See also commit 6863f5643d ("kbuild: allow Clang to find unused static
inline functions for W=1 build").

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/20240909105314.928302-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-09-09 16:04:25 -04:00
Steven Rostedt
af17814334 tracing/osnoise: Fix build when timerlat is not enabled
To fix some critical section races, the interface_lock was added to a few
locations. One of those locations was above where the interface_lock was
declared, so the declaration was moved up before that usage.
Unfortunately, where it was placed was inside a CONFIG_TIMERLAT_TRACER
ifdef block. As the interface_lock is used outside that config, this broke
the build when CONFIG_OSNOISE_TRACER was enabled but
CONFIG_TIMERLAT_TRACER was not.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Helena Anna" <helena.anna.dubel@intel.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Tomas Glozar <tglozar@redhat.com>
Link: https://lore.kernel.org/20240909103231.23a289e2@gandalf.local.home
Fixes: e6a53481da ("tracing/timerlat: Only clear timer if a kthread exists")
Reported-by: "Bityutskiy, Artem" <artem.bityutskiy@intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-09-09 16:03:57 -04:00
Jiri Olsa
900f362e20 bpf: Fix uprobe multi pid filter check
Uprobe multi link does its own process (thread leader) filtering before
running the bpf program by comparing task's vm pointers.

But as Oleg pointed out there can be processes sharing the vm (CLONE_VM),
so we can't just compare task->vm pointers, but instead we need to use
same_thread_group call.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/bpf/20240905115124.1503998-2-jolsa@kernel.org
2024-09-05 12:43:22 -07:00
Steven Rostedt
5bfbcd1ee5 tracing/timerlat: Add interface_lock around clearing of kthread in stop_kthread()
The timerlat interface will get and put the task that is part of the
"kthread" field of the osn_var to keep it around until all references are
released. But here's a race in the "stop_kthread()" code that will call
put_task_struct() on the kthread if it is not a kernel thread. This can
race with the releasing of the references to that task struct and the
put_task_struct() can be called twice when it should have been called just
once.

Take the interface_lock() in stop_kthread() to synchronize this change.
But to do so, the function stop_per_cpu_kthreads() needs to change the
loop from for_each_online_cpu() to for_each_possible_cpu() and remove the
cpu_read_lock(), as the interface_lock can not be taken while the cpu
locks are held. The only side effect of this change is that it may do some
extra work, as the per_cpu variables of the offline CPUs would not be set
anyway, and would simply be skipped in the loop.

Remove unneeded "return;" in stop_kthread().

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Link: https://lore.kernel.org/20240905113359.2b934242@gandalf.local.home
Fixes: e88ed227f6 ("tracing/timerlat: Add user-space interface")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-09-05 12:01:37 -04:00
Steven Rostedt
e6a53481da tracing/timerlat: Only clear timer if a kthread exists
The timerlat tracer can use user space threads to check for osnoise and
timer latency. If the program using this is killed via a SIGTERM, the
threads are shutdown one at a time and another tracing instance can start
up resetting the threads before they are fully closed. That causes the
hrtimer assigned to the kthread to be shutdown and freed twice when the
dying thread finally closes the file descriptors, causing a use-after-free
bug.

Only cancel the hrtimer if the associated thread is still around. Also add
the interface_lock around the resetting of the tlat_var->kthread.

Note, this is just a quick fix that can be backported to stable. A real
fix is to have a better synchronization between the shutdown of old
threads and the starting of new ones.

Link: https://lore.kernel.org/all/20240820130001.124768-1-tglozar@redhat.com/

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Link: https://lore.kernel.org/20240905085330.45985730@gandalf.local.home
Fixes: e88ed227f6 ("tracing/timerlat: Add user-space interface")
Reported-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-09-05 11:30:23 -04:00
Steven Rostedt
177e1cc2f4 tracing/osnoise: Use a cpumask to know what threads are kthreads
The start_kthread() and stop_thread() code was not always called with the
interface_lock held. This means that the kthread variable could be
unexpectedly changed causing the kthread_stop() to be called on it when it
should not have been, leading to:

 while true; do
   rtla timerlat top -u -q & PID=$!;
   sleep 5;
   kill -INT $PID;
   sleep 0.001;
   kill -TERM $PID;
   wait $PID;
  done

Causing the following OOPS:

 Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN PTI
 KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
 CPU: 5 UID: 0 PID: 885 Comm: timerlatu/5 Not tainted 6.11.0-rc4-test-00002-gbc754cc76d1b-dirty #125 a533010b71dab205ad2f507188ce8c82203b0254
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
 RIP: 0010:hrtimer_active+0x58/0x300
 Code: 48 c1 ee 03 41 54 48 01 d1 48 01 d6 55 53 48 83 ec 20 80 39 00 0f 85 30 02 00 00 49 8b 6f 30 4c 8d 75 10 4c 89 f0 48 c1 e8 03 <0f> b6 3c 10 4c 89 f0 83 e0 07 83 c0 03 40 38 f8 7c 09 40 84 ff 0f
 RSP: 0018:ffff88811d97f940 EFLAGS: 00010202
 RAX: 0000000000000002 RBX: ffff88823c6b5b28 RCX: ffffed10478d6b6b
 RDX: dffffc0000000000 RSI: ffffed10478d6b6c RDI: ffff88823c6b5b28
 RBP: 0000000000000000 R08: ffff88823c6b5b58 R09: ffff88823c6b5b60
 R10: ffff88811d97f957 R11: 0000000000000010 R12: 00000000000a801d
 R13: ffff88810d8b35d8 R14: 0000000000000010 R15: ffff88823c6b5b28
 FS:  0000000000000000(0000) GS:ffff88823c680000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000561858ad7258 CR3: 000000007729e001 CR4: 0000000000170ef0
 Call Trace:
  <TASK>
  ? die_addr+0x40/0xa0
  ? exc_general_protection+0x154/0x230
  ? asm_exc_general_protection+0x26/0x30
  ? hrtimer_active+0x58/0x300
  ? __pfx_mutex_lock+0x10/0x10
  ? __pfx_locks_remove_file+0x10/0x10
  hrtimer_cancel+0x15/0x40
  timerlat_fd_release+0x8e/0x1f0
  ? security_file_release+0x43/0x80
  __fput+0x372/0xb10
  task_work_run+0x11e/0x1f0
  ? _raw_spin_lock+0x85/0xe0
  ? __pfx_task_work_run+0x10/0x10
  ? poison_slab_object+0x109/0x170
  ? do_exit+0x7a0/0x24b0
  do_exit+0x7bd/0x24b0
  ? __pfx_migrate_enable+0x10/0x10
  ? __pfx_do_exit+0x10/0x10
  ? __pfx_read_tsc+0x10/0x10
  ? ktime_get+0x64/0x140
  ? _raw_spin_lock_irq+0x86/0xe0
  do_group_exit+0xb0/0x220
  get_signal+0x17ba/0x1b50
  ? vfs_read+0x179/0xa40
  ? timerlat_fd_read+0x30b/0x9d0
  ? __pfx_get_signal+0x10/0x10
  ? __pfx_timerlat_fd_read+0x10/0x10
  arch_do_signal_or_restart+0x8c/0x570
  ? __pfx_arch_do_signal_or_restart+0x10/0x10
  ? vfs_read+0x179/0xa40
  ? ksys_read+0xfe/0x1d0
  ? __pfx_ksys_read+0x10/0x10
  syscall_exit_to_user_mode+0xbc/0x130
  do_syscall_64+0x74/0x110
  ? __pfx___rseq_handle_notify_resume+0x10/0x10
  ? __pfx_ksys_read+0x10/0x10
  ? fpregs_restore_userregs+0xdb/0x1e0
  ? fpregs_restore_userregs+0xdb/0x1e0
  ? syscall_exit_to_user_mode+0x116/0x130
  ? do_syscall_64+0x74/0x110
  ? do_syscall_64+0x74/0x110
  ? do_syscall_64+0x74/0x110
  entry_SYSCALL_64_after_hwframe+0x71/0x79
 RIP: 0033:0x7ff0070eca9c
 Code: Unable to access opcode bytes at 0x7ff0070eca72.
 RSP: 002b:00007ff006dff8c0 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 00007ff0070eca9c
 RDX: 0000000000000400 RSI: 00007ff006dff9a0 RDI: 0000000000000003
 RBP: 00007ff006dffde0 R08: 0000000000000000 R09: 00007ff000000ba0
 R10: 00007ff007004b08 R11: 0000000000000246 R12: 0000000000000003
 R13: 00007ff006dff9a0 R14: 0000000000000007 R15: 0000000000000008
  </TASK>
 Modules linked in: snd_hda_intel snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec snd_hwdep snd_hda_core
 ---[ end trace 0000000000000000 ]---

This is because it would mistakenly call kthread_stop() on a user space
thread making it "exit" before it actually exits.

Since kthreads are created based on global behavior, use a cpumask to know
when kthreads are running and that they need to be shutdown before
proceeding to do new work.

Link: https://lore.kernel.org/all/20240820130001.124768-1-tglozar@redhat.com/

This was debugged by using the persistent ring buffer:

Link: https://lore.kernel.org/all/20240823013902.135036960@goodmis.org/

Note, locking was originally used to fix this, but that proved to cause too
many deadlocks to work around:

  https://lore.kernel.org/linux-trace-kernel/20240823102816.5e55753b@gandalf.local.home/

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Link: https://lore.kernel.org/20240904103428.08efdf4c@gandalf.local.home
Fixes: e88ed227f6 ("tracing/timerlat: Add user-space interface")
Reported-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-09-05 11:30:22 -04:00
Peter Zijlstra
04b01625da perf/uprobe: split uprobe_unregister()
With uprobe_unregister() having grown a synchronize_srcu(), it becomes
fairly slow to call. Esp. since both users of this API call it in a
loop.

Peel off the sync_srcu() and do it once, after the loop.

We also need to add uprobe_unregister_sync() into uprobe_register()'s
error handling path, as we need to be careful about returning to the
caller before we have a guarantee that partially attached consumer won't
be called anymore. This is an unlikely slow path and this should be
totally fine to be slow in the case of a failed attach.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Co-developed-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20240903174603.3554182-6-andrii@kernel.org
2024-09-05 16:56:14 +02:00
Andrii Nakryiko
59da880afe uprobes: get rid of enum uprobe_filter_ctx in uprobe filter callbacks
It serves no purpose beyond adding unnecessray argument passed to the
filter callback. Just get rid of it, no one is actually using it.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20240903174603.3554182-4-andrii@kernel.org
2024-09-05 16:56:14 +02:00
Oleg Nesterov
5fe6e308ab bpf: Fix use-after-free in bpf_uprobe_multi_link_attach()
If bpf_link_prime() fails, bpf_uprobe_multi_link_attach() goes to the
error_free label and frees the array of bpf_uprobe's without calling
bpf_uprobe_unregister().

This leaks bpf_uprobe->uprobe and worse, this frees bpf_uprobe->consumer
without removing it from the uprobe->consumers list.

Fixes: 89ae89f53d ("bpf: Add multi uprobe link")
Closes: https://lore.kernel.org/all/000000000000382d39061f59f2dd@google.com/
Reported-by: syzbot+f7a1c2c2711e4a780f19@syzkaller.appspotmail.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: syzbot+f7a1c2c2711e4a780f19@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240813152524.GA7292@redhat.com
2024-09-05 16:56:13 +02:00
Zheng Yejian
49aa8a1f4d tracing: Avoid possible softlockup in tracing_iter_reset()
In __tracing_open(), when max latency tracers took place on the cpu,
the time start of its buffer would be updated, then event entries with
timestamps being earlier than start of the buffer would be skipped
(see tracing_iter_reset()).

Softlockup will occur if the kernel is non-preemptible and too many
entries were skipped in the loop that reset every cpu buffer, so add
cond_resched() to avoid it.

Cc: stable@vger.kernel.org
Fixes: 2f26ebd549 ("tracing: use timestamp to determine start of latency traces")
Link: https://lore.kernel.org/20240827124654.3817443-1-zhengyejian@huaweicloud.com
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Zheng Yejian <zhengyejian@huaweicloud.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-09-05 10:18:48 -04:00
Ingo Molnar
95c13662b6 Merge branch 'perf/urgent' into perf/core, to pick up fixes
This also refreshes the -rc1 based branch to -rc5.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2024-09-05 11:17:43 +02:00
Steven Rostedt
ef2bd81d0c tracing: Add option to set an instance to be the trace_printk destination
Add a option "trace_printk_dest" that will make the tracing instance the
location that trace_printk() will go to. This is useful if the
trace_printk or one of the top level tracers is too noisy and there's a
need to separate the two. Then an instance can be created, the
trace_printk can be set to go there instead, where it will not be lost in
the noise of the top level tracer.

Note, only one instance can be the destination of trace_printk at a time.
If an instance sets this flag, the instance that had it set will have it
cleared. There is always one instance that has this set. By default, that
is the top instance. This flag cannot be cleared from the top instance.
Doing so will result in an -EINVAL. The only way this flag can be cleared
from the top instance is by another instance setting it.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineeth Pillai <vineeth@bitbyteword.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexander Aring <aahringo@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Jonathan Corbet" <corbet@lwn.net>
Link: https://lore.kernel.org/20240823014019.545459018@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-26 13:54:08 -04:00
Steven Rostedt
9b7bdf6f6e tracing: Have trace_printk not use binary prints if boot buffer
If the persistent boot mapped ring buffer is used for trace_printk(),
force it to not use the binary versions. trace_printk() by default uses
bin_printf() that only saves the pointer to the format and not the format
itself inside the ring buffer. But for a persistent buffer that is read
after reboot, the pointers to the format strings may not be the same, or
worse, not even exist! Instead, just force the more robust, but slower,
version that does the formatting before saving into the ring buffer.

The boot mapped buffer can now be used for trace_printk and friends!

Using the trace_printk() and the persistent buffer was used to debug the
issue with the osnoise tracer:

Link: https://lore.kernel.org/all/20240822103443.6a6ae051@gandalf.local.home/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineeth Pillai <vineeth@bitbyteword.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexander Aring <aahringo@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Jonathan Corbet" <corbet@lwn.net>
Link: https://lore.kernel.org/20240823014019.386925800@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-26 13:54:08 -04:00
Steven Rostedt
ddb8ea9e5a tracing: Allow trace_printk() to go to other instance buffers
Currently, trace_printk() just goes to the top level ring buffer. But
there may be times that it should go to one of the instances created by
the kernel command line.

Add a new trace_instance flag: traceprintk (also can use "printk" or
"trace_printk" as people tend to forget the actual flag name).

  trace_instance=foo^traceprintk

Will assign the trace_printk to this buffer at boot up.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineeth Pillai <vineeth@bitbyteword.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexander Aring <aahringo@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Jonathan Corbet" <corbet@lwn.net>
Link: https://lore.kernel.org/20240823014019.226694946@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-26 13:54:08 -04:00
Steven Rostedt
b6fc31b687 tracing: Add "traceoff" flag to boot time tracing instances
Add a "flags" delimiter (^) to the "trace_instance" kernel command line
parameter, and add the "traceoff" flag. The format is:

   trace_instance=<name>[^<flag1>[^<flag2>]][@<memory>][,<events>]

The code allows for more than one flag to be added, but currently only
"traceoff" is done so.

The motivation for this change came from debugging with the persistent
ring buffer and having trace_printk() writing to it. The trace_printk
calls are always enabled, and the boot after the crash was having the
unwanted trace_printks from the current boot inject into the ring buffer
with the trace_printks of the crash kernel, making the output very
confusing.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineeth Pillai <vineeth@bitbyteword.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexander Aring <aahringo@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Jonathan Corbet" <corbet@lwn.net>
Link: https://lore.kernel.org/20240823014019.053229958@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-26 13:54:08 -04:00
Vincent Donnefort
eb2dcde9f9 ring-buffer: Align meta-page to sub-buffers for improved TLB usage
Previously, the mapped ring-buffer layout caused misalignment between
the meta-page and sub-buffers when the sub-buffer size was not a
multiple of PAGE_SIZE. This prevented hardware with larger TLB entries
from utilizing them effectively.

Add a padding with the zero-page between the meta-page and sub-buffers.
Also update the ring-buffer map_test to verify that padding.

Link: https://lore.kernel.org/20240628104611.1443542-1-vdonnefort@google.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-26 13:42:23 -04:00
Steven Rostedt
d0f2d6e951 ring-buffer: Add magic and struct size to boot up meta data
Add a magic number as well as save the struct size of the ring_buffer_meta
structure in the meta data to also use as validation. Updating the magic
number could be used to force a invalidation between kernel versions, and
saving the structure size is also a good method to make sure the content
is what is expected.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/20240815115032.0c197b32@rorschach.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-26 13:34:22 -04:00
Steven Rostedt
bca704f62d ring-buffer: Don't reset persistent ring-buffer meta saved addresses
The text and data address is saved in the meta data so that it can be used
to know the delta of the text and data addresses of the last boot compared
to the text and data addresses of the current boot. The delta is used to
convert function pointer entries in the ring buffer to something that can
be used by kallsyms (note this only works for built-in functions).

But the saved addresses get reset on boot up. If the buffer is not used
and there's another reboot, then the saved text and data addresses will be
of the last boot and not that of the boot that created the content in the
ring buffer.

To get an idea of the issue:

 # trace-cmd start -B boot_mapped -p function
 # reboot
 # trace-cmd show -B boot_mapped | tail
           <...>-1       [000] d..1.   461.983243: native_apic_msr_write <-native_kick_ap
           <...>-1       [000] d..1.   461.983244: __pfx_native_apic_msr_eoi <-native_kick_ap
           <...>-1       [000] d..1.   461.983244: reserve_irq_vector_locked <-native_kick_ap
           <...>-1       [000] d..1.   461.983262: branch_emulate_op <-native_kick_ap
           <...>-1       [000] d..1.   461.983262: __ia32_sys_ia32_pread64 <-native_kick_ap
           <...>-1       [000] d..1.   461.983263: native_kick_ap <-__smpboot_create_thread
           <...>-1       [000] d..1.   461.983263: store_cache_disable <-native_kick_ap
           <...>-1       [000] d..1.   461.983279: acpi_power_off_prepare <-native_kick_ap
           <...>-1       [000] d..1.   461.983280: __pfx_acpi_ns_delete_node <-acpi_suspend_enter
           <...>-1       [000] d..1.   461.983280: __pfx_acpi_os_release_lock <-acpi_suspend_enter
 # reboot
 # trace-cmd show -B boot_mapped  |tail
           <...>-1       [000] d..1.   461.983243: 0xffffffffa9669220 <-0xffffffffa965f3db
           <...>-1       [000] d..1.   461.983244: 0xffffffffa96690f0 <-0xffffffffa965f3db
           <...>-1       [000] d..1.   461.983244: 0xffffffffa9663fa0 <-0xffffffffa965f3db
           <...>-1       [000] d..1.   461.983262: 0xffffffffa9672e80 <-0xffffffffa965f3e0
           <...>-1       [000] d..1.   461.983262: 0xffffffffa962b940 <-0xffffffffa965f3ec
           <...>-1       [000] d..1.   461.983263: 0xffffffffa965f540 <-0xffffffffa96e1362
           <...>-1       [000] d..1.   461.983263: 0xffffffffa963c940 <-0xffffffffa965f55b
           <...>-1       [000] d..1.   461.983279: 0xffffffffa9ee30c0 <-0xffffffffa965f59b
           <...>-1       [000] d..1.   461.983280: 0xffffffffa9f16c10 <-0xffffffffa9ee3157
           <...>-1       [000] d..1.   461.983280: 0xffffffffa9ee02e0 <-0xffffffffa9ee3157

By not updating the saved text and data addresses in the meta data at
every boot up and only updating them when the buffer is reset, it
allows multiple boots to see the same data.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/20240815113629.0dc90af8@rorschach.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-26 13:33:53 -04:00
Alexei Starovoitov
50c374c6d1 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Cross-merge bpf fixes after downstream PR including
important fixes (from bpf-next point of view):
commit 41c24102af ("selftests/bpf: Filter out _GNU_SOURCE when compiling test_cpp")
commit fdad456cbc ("bpf: Fix updating attached freplace prog in prog_array map")

No conflicts.

Adjacent changes in:
include/linux/bpf_verifier.h
kernel/bpf/verifier.c
tools/testing/selftests/bpf/Makefile

Link: https://lore.kernel.org/bpf/20240813234307.82773-1-alexei.starovoitov@gmail.com/
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-22 09:48:44 -07:00
Masami Hiramatsu (Google)
bc754cc76d tracing: Fix memory leak in fgraph storage selftest
With ftrace boot-time selftest, kmemleak reported some memory leaks in
the new test case for function graph storage for multiple tracers.

unreferenced object 0xffff888005060080 (size 32):
  comm "swapper/0", pid 1, jiffies 4294676440
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 20 10 06 05 80 88 ff ff  ........ .......
    54 0c 1e 81 ff ff ff ff 00 00 00 00 00 00 00 00  T...............
  backtrace (crc 7c93416c):
    [<000000000238ee6f>] __kmalloc_cache_noprof+0x11f/0x2a0
    [<0000000033d2b6c5>] enter_record+0xe8/0x150
    [<0000000054c38424>] match_records+0x1cd/0x230
    [<00000000c775b63d>] ftrace_set_hash+0xff/0x380
    [<000000007bf7208c>] ftrace_set_filter+0x70/0x90
    [<00000000a5c08dda>] test_graph_storage_multi+0x2e/0xf0
    [<000000006ba028ca>] trace_selftest_startup_function_graph+0x1e8/0x260
    [<00000000a715d3eb>] run_tracer_selftest+0x111/0x190
    [<00000000395cbf90>] register_tracer+0xdf/0x1f0
    [<0000000093e67f7b>] do_one_initcall+0x141/0x3b0
    [<00000000c591b682>] do_initcall_level+0x82/0xa0
    [<000000004e4c6600>] do_initcalls+0x43/0x70
    [<0000000034f3c4e4>] kernel_init_freeable+0x170/0x1f0
    [<00000000c7a5dab2>] kernel_init+0x1a/0x1a0
    [<00000000ea105947>] ret_from_fork+0x3a/0x50
    [<00000000a1932e84>] ret_from_fork_asm+0x1a/0x30
...

This means filter hash allocated for the fixtures are not correctly
released after the test.

Free those hash lists after tests are done and split the loop for
initialize fixture and register fixture for rollback.

Fixes: dd120af2d5 ("ftrace: Add multiple fgraph storage selftest")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/172411539857.28895.13119957560263401102.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-21 15:10:33 -04:00
Masami Hiramatsu (Google)
a069a22f39 tracing: fgraph: Fix to add new fgraph_ops to array after ftrace_startup_subops()
Since the register_ftrace_graph() assigns a new fgraph_ops to
fgraph_array before registring it by ftrace_startup_subops(), the new
fgraph_ops can be used in function_graph_enter().

In most cases, it is still OK because those fgraph_ops's hashtable is
already initialized by ftrace_set_filter*() etc.

But if a user registers a new fgraph_ops which does not initialize the
hash list, ftrace_ops_test() in function_graph_enter() causes a NULL
pointer dereference BUG because fgraph_ops->ops.func_hash is NULL.

This can be reproduced by the below commands because function profiler's
fgraph_ops does not initialize the hash list;

 # cd /sys/kernel/tracing
 # echo function_graph > current_tracer
 # echo 1 > function_profile_enabled

To fix this problem, add a new fgraph_ops to fgraph_array after
ftrace_startup_subops(). Thus, until the new fgraph_ops is initialized,
we will see fgraph_stub on the corresponding fgraph_array entry.

Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/172398528350.293426.8347220120333730248.stgit@devnote2
Fixes: c132be2c4f ("function_graph: Have the instances use their own ftrace_ops for filtering")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-21 13:49:59 -04:00
Matteo Croce
7f6287417b bpf: Allow bpf_current_task_under_cgroup() with BPF_CGROUP_*
The helper bpf_current_task_under_cgroup() currently is only allowed for
tracing programs, allow its usage also in the BPF_CGROUP_* program types.

Move the code from kernel/trace/bpf_trace.c to kernel/bpf/helpers.c,
so it compiles also without CONFIG_BPF_EVENTS.

This will be used in systemd-networkd to monitor the sysctl writes,
and filter it's own writes from others:
https://github.com/systemd/systemd/pull/32212

Signed-off-by: Matteo Croce <teknoraver@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240819162805.78235-3-technoboy85@gmail.com
2024-08-19 15:25:30 -07:00
Valentin Schneider
32a9f26e5e rcu: Rename rcu_momentary_dyntick_idle() into rcu_momentary_eqs()
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, replace "dyntick_idle" into "eqs" to drop the dyntick
reference.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
2024-08-15 21:30:42 +05:30
Steven Rostedt
4c57d0be52 tracing/fgraph: Have fgraph handle previous boot function addresses
Update the function graph code to modify the function addresses for a
previous boot buffer so that it matches the current kallsyms (note this
does not handle module addresses, yet).

After a reboot, instead of seeing:

 # trace-cmd show -B boot_mapped | tail -n30
       swapper/0-1       [000] d..2.    56.286470:  0)   0.481 us    |                    0xffffffff925da5c4();
       swapper/0-1       [000] d....    56.286471:  0)   4.065 us    |                  }
       swapper/0-1       [000] d....    56.286471:  0)   4.920 us    |                }
       swapper/0-1       [000] d..1.    56.286472:  0)               |                0xffffffff92536254() {
       swapper/0-1       [000] d..1.    56.286472:  0) + 28.974 us   |                  0xffffffff92534e30();
       swapper/0-1       [000] d....    56.286516:  0) + 43.881 us   |                }
       swapper/0-1       [000] d..1.    56.286517:  0)               |                0xffffffff925136c4() {
       swapper/0-1       [000] d..1.    56.286518:  0)               |                  0xffffffff92514a14() {
       swapper/0-1       [000] d..1.    56.286518:  0)   6.003 us    |                    0xffffffff92514200();
       swapper/0-1       [000] d....    56.286529:  0) + 11.510 us   |                  }
       swapper/0-1       [000] d....    56.286529:  0) + 12.895 us   |                }
       swapper/0-1       [000] d....    56.286530:  0) ! 382.884 us  |              }
       swapper/0-1       [000] d..1.    56.286530:  0)               |              0xffffffff92536444() {
       swapper/0-1       [000] d..1.    56.286531:  0)               |                0xffffffff92536254() {
       swapper/0-1       [000] d..1.    56.286531:  0) + 26.335 us   |                  0xffffffff92534e30();
       swapper/0-1       [000] d....    56.286560:  0) + 29.511 us   |                }
       swapper/0-1       [000] d....    56.286561:  0) + 30.452 us   |              }
       swapper/0-1       [000] d..1.    56.286562:  0)               |              0xffffffff9253c014() {
       swapper/0-1       [000] d..1.    56.286562:  0)               |                0xffffffff9253bed4() {
       swapper/0-1       [000] d..1.    56.286563:  0) + 13.465 us   |                  0xffffffff92536684();
       swapper/0-1       [000] d....    56.286577:  0) + 14.651 us   |                }
       swapper/0-1       [000] d....    56.286577:  0) + 15.821 us   |              }
       swapper/0-1       [000] d..1.    56.286578:  0)   0.667 us    |              0xffffffff92547074();
       swapper/0-1       [000] d..1.    56.286579:  0)   0.453 us    |              0xffffffff924f35c4();
       swapper/0-1       [000] d....    56.286580:  0) # 3906.348 us |            }
       swapper/0-1       [000] d..1.    56.286581:  0)               |            0xffffffff92531a14() {
       swapper/0-1       [000] d..1.    56.286581:  0)   0.518 us    |              0xffffffff92505cb4();
       swapper/0-1       [000] d..1.    56.286595:  0)               |              0xffffffff92db83c4() {
       swapper/0-1       [000] d..1.    56.286596:  0)               |                0xffffffff92dec2e4() {
       swapper/0-1       [000] d..1.    56.286597:  0)               |                  0xffffffff92db5304() {

It now shows:

 # trace-cmd show -B boot_mapped | tail -n30
       swapper/0-1       [000] d..2.   363.079099:  0)   0.483 us    |                    preempt_count_sub();
       swapper/0-1       [000] d....   363.079100:  0)   4.112 us    |                  }
       swapper/0-1       [000] d....   363.079101:  0)   4.979 us    |                }
       swapper/0-1       [000] d..1.   363.079101:  0)               |                disable_local_APIC() {
       swapper/0-1       [000] d..1.   363.079102:  0) + 29.153 us   |                  clear_local_APIC.part.0();
       swapper/0-1       [000] d....   363.079148:  0) + 46.517 us   |                }
       swapper/0-1       [000] d..1.   363.079149:  0)               |                mcheck_cpu_clear() {
       swapper/0-1       [000] d..1.   363.079149:  0)               |                  mce_intel_feature_clear() {
       swapper/0-1       [000] d..1.   363.079150:  0)   5.871 us    |                    lmce_supported();
       swapper/0-1       [000] d....   363.079161:  0) + 11.340 us   |                  }
       swapper/0-1       [000] d....   363.079161:  0) + 12.638 us   |                }
       swapper/0-1       [000] d....   363.079162:  0) ! 383.518 us  |              }
       swapper/0-1       [000] d..1.   363.079162:  0)               |              lapic_shutdown() {
       swapper/0-1       [000] d..1.   363.079163:  0)               |                disable_local_APIC() {
       swapper/0-1       [000] d..1.   363.079163:  0) + 26.144 us   |                  clear_local_APIC.part.0();
       swapper/0-1       [000] d....   363.079192:  0) + 29.424 us   |                }
       swapper/0-1       [000] d....   363.079192:  0) + 30.376 us   |              }
       swapper/0-1       [000] d..1.   363.079193:  0)               |              restore_boot_irq_mode() {
       swapper/0-1       [000] d..1.   363.079194:  0)               |                native_restore_boot_irq_mode() {
       swapper/0-1       [000] d..1.   363.079194:  0) + 13.863 us   |                  disconnect_bsp_APIC();
       swapper/0-1       [000] d....   363.079209:  0) + 14.933 us   |                }
       swapper/0-1       [000] d....   363.079209:  0) + 16.009 us   |              }
       swapper/0-1       [000] d..1.   363.079210:  0)   0.694 us    |              hpet_disable();
       swapper/0-1       [000] d..1.   363.079211:  0)   0.511 us    |              iommu_shutdown_noop();
       swapper/0-1       [000] d....   363.079212:  0) # 3980.260 us |            }
       swapper/0-1       [000] d..1.   363.079212:  0)               |            native_machine_emergency_restart() {
       swapper/0-1       [000] d..1.   363.079213:  0)   0.495 us    |              tboot_shutdown();
       swapper/0-1       [000] d..1.   363.079230:  0)               |              acpi_reboot() {
       swapper/0-1       [000] d..1.   363.079231:  0)               |                acpi_reset() {
       swapper/0-1       [000] d..1.   363.079232:  0)               |                  acpi_os_write_port() {

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/20240813171257.478901820@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-15 08:35:48 -04:00
Steven Rostedt (Google)
29a02ec665 tracing: Allow boot instances to use reserve_mem boot memory
Allow boot instances to use memory reserved by the reserve_mem boot
option.

  reserve_mem=12M:4096:trace  trace_instance=boot_mapped@trace

The above will allocate 12 megs with 4096 alignment and label it "trace".
The second parameter will create a "boot_mapped" instance and use the
memory reserved and labeled as "trace" as the memory for the ring buffer.

That will create an instance called "boot_mapped":

  /sys/kernel/tracing/instances/boot_mapped

Note, because the ring buffer is using a defined memory ranged, it will
act just like a memory mapped ring buffer. It will not have a snapshot
buffer, as it can't swap out the buffer. The snapshot files as well as any
tracers that uses a snapshot will not be present in the boot_mapped
instance.

Also note that reserve_mem is not reliable in acquiring the same physical
memory at each soft reboot. It is possible that KALSR could map the kernel
at the previous boot memory location forcing the reserve_mem to return a
different memory location. In this case, the previous ring buffer will be
lost.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/20240815082811.669f7d8c@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-15 08:34:48 -04:00
Steven Rostedt
6d02eefecc tracing: Fix ifdef of snapshots to not prevent last_boot_info file
The mapping of the ring buffer to memory allocated at boot up will also
expose a "last_boot_info" to help tooling to read the raw data from the
last boot. As instances that have their ring buffer mapped to fixed
memory cannot perform snapshots, they can either have the "snapshot" file
or the "last_boot_info" file, but not both.

The code that added the "last_boot_info" file failed to notice that the
"snapshot" creation was inside a "#ifdef CONFIG_TRACER_SNAPSHOT" and
incorrectly placed the creation of the "last_boot_info" file within the
ifdef block. Not only does it cause a warning when CONFIG_TRACER_SNAPSHOT
is not enabled, it also incorrectly prevents the file from appearing.

Link: https://lore.kernel.org/all/20240719102640.718554-1-arnd@kernel.org/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reported-by: Arnd Bergmann <arnd@kernel.org>
Link: https://lore.kernel.org/20240719101312.3d4ac707@rorschach.local.home
Fixes: 7a1d1e4b96 ("tracing/ring-buffer: Add last_boot_info file to boot instance")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-14 17:01:03 -04:00
Steven Rostedt
ee057c8c19 Linux 6.11-rc3
-----BEGIN PGP SIGNATURE-----
 
 iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAma5LLIeHHRvcnZhbGRz
 QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGwUAIAJNwbkdgTIqEsyBU
 wsFcXGaFSsGJNbTulINJb34jl2gD2yr4pmnnrA0NePW1TUKOnx169hNMF8NWbr/A
 0cHIREV9cyfnm/kzAcnHn7cWLSmsKd+x3TnCbCyodDZQDJzdLmw3LQG+4dTNJbw1
 WtJO/EoaU4qaydW2VxtApw54sirq5bopZz7rpcRapA1afzbA2TUDbnnuEWjm9KCF
 5K+RZTJZA/xI9gqEwJB+/p5FglW4n/T3xcDwaQp5uFsDskgV5e1AUrRLM+icTsem
 0Egrs8Ca2Vp4oBM+r9miCSwjRu04jLKyuu20p7AN8zXLyN7WGAjduS15Dv+aHRZ/
 9XABZs0=
 =/T17
 -----END PGP SIGNATURE-----

Merge tag 'v6.11-rc3' into trace/ring-buffer/core

The "reserve_mem" kernel command line parameter has been pulled into
v6.11. Merge the latest -rc3 to allow the persistent ring buffer memory to
be able to be mapped at the address specified by the "reserve_mem" command
line parameter.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-14 16:59:28 -04:00
Steven Rostedt
d0949cd44a tracing: Return from tracing_buffers_read() if the file has been closed
When running the following:

 # cd /sys/kernel/tracing/
 # echo 1 > events/sched/sched_waking/enable
 # echo 1 > events/sched/sched_switch/enable
 # echo 0 > tracing_on
 # dd if=per_cpu/cpu0/trace_pipe_raw of=/tmp/raw0.dat

The dd task would get stuck in an infinite loop in the kernel. What would
happen is the following:

When ring_buffer_read_page() returns -1 (no data) then a check is made to
see if the buffer is empty (as happens when the page is not full), it will
call wait_on_pipe() to wait until the ring buffer has data. When it is it
will try again to read data (unless O_NONBLOCK is set).

The issue happens when there's a reader and the file descriptor is closed.
The wait_on_pipe() will return when that is the case. But this loop will
continue to try again and wait_on_pipe() will again return immediately and
the loop will continue and never stop.

Simply check if the file was closed before looping and exit out if it is.

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240808235730.78bf63e5@rorschach.local.home
Fixes: 2aa043a55b ("tracing/ring-buffer: Fix wait_on_pipe() race")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-09 12:59:35 -04:00