ops.cpu_acquire() is currently called with 0 kf_maks which is interpreted as
SCX_KF_UNLOCKED which allows all unlocked kfuncs, but ops.cpu_acquire() is
called from balance_one() under the rq lock and should only be allowed call
kfuncs that are safe under the rq lock. Update it to use SCX_KF_REST.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David Vernet <void@manifault.com>
Cc: Zhao Mengmeng <zhaomzhao@126.com>
Link: http://lkml.kernel.org/r/ZzYvf2L3rlmjuKzh@slm.duckdns.org
Fixes: 245254f708 ("sched_ext: Implement sched_ext_ops.cpu_acquire/release()")
With some recent proposed changes [1] in the deadline server code,
it has caused a test failure in test_cpuset_prs.sh when a change
is being made to an isolated partition. This is due to failing
the cpuset_cpumask_can_shrink() check for SCHED_DEADLINE tasks at
validate_change().
This is actually a false positive as the failed test case involves an
isolated partition with load balancing disabled. The deadline check
is not meaningful in this case and the users should know what they
are doing.
Fix this by doing the cpuset_cpumask_can_shrink() check only when loading
balanced is enabled. Also change its arguments to use effective_cpus
for the current cpuset and user_xcpus() as an approiximation for the
target effective_cpus as the real effective_cpus hasn't been fully
computed yet as this early stage.
As the check isn't comprehensive, there may be false positives or
negatives. We may have to revise the code to do a more thorough check
in the future if this becomes a concern.
[1] https://lore.kernel.org/lkml/82be06c1-6d6d-4651-86c9-bcc828cbcb80@redhat.com/T/#t
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The events of a memory mapped ring buffer from the previous boot should
not be mixed in with events from the current boot. There's meta data that
is used to handle KASLR so that function names can be shown properly.
Also, since the timestamps of the previous boot have no meaning to the
timestamps of the current boot, having them intermingled in a buffer can
also cause confusion because there could possibly be events in the future.
When a trace is activated the meta data is reset so that the pointers of
are now processed for the new address space. The trace buffers are reset
when tracing starts for the first time. The problem here is that the reset
only happens on online CPUs. If a CPU is offline, it does not get reset.
To demonstrate the issue, a previous boot had tracing enabled in the boot
mapped ring buffer on reboot. On the following boot, tracing has not been
started yet so the function trace from the previous boot is still visible.
# trace-cmd show -B boot_mapped -c 3 | tail
<idle>-0 [003] d.h2. 156.462395: __rcu_read_lock <-cpu_emergency_disable_virtualization
<idle>-0 [003] d.h2. 156.462396: vmx_emergency_disable_virtualization_cpu <-cpu_emergency_disable_virtualization
<idle>-0 [003] d.h2. 156.462396: __rcu_read_unlock <-__sysvec_reboot
<idle>-0 [003] d.h2. 156.462397: stop_this_cpu <-__sysvec_reboot
<idle>-0 [003] d.h2. 156.462397: set_cpu_online <-stop_this_cpu
<idle>-0 [003] d.h2. 156.462397: disable_local_APIC <-stop_this_cpu
<idle>-0 [003] d.h2. 156.462398: clear_local_APIC <-disable_local_APIC
<idle>-0 [003] d.h2. 156.462574: mcheck_cpu_clear <-stop_this_cpu
<idle>-0 [003] d.h2. 156.462575: mce_intel_feature_clear <-stop_this_cpu
<idle>-0 [003] d.h2. 156.462575: lmce_supported <-mce_intel_feature_clear
Now, if CPU 3 is taken offline, and tracing is started on the memory
mapped ring buffer, the events from the previous boot in the CPU 3 ring
buffer is not reset. Now those events are using the meta data from the
current boot and produces just hex values.
# echo 0 > /sys/devices/system/cpu/cpu3/online
# trace-cmd start -B boot_mapped -p function
# trace-cmd show -B boot_mapped -c 3 | tail
<idle>-0 [003] d.h2. 156.462395: 0xffffffff9a1e3194 <-0xffffffff9a0f655e
<idle>-0 [003] d.h2. 156.462396: 0xffffffff9a0a1d24 <-0xffffffff9a0f656f
<idle>-0 [003] d.h2. 156.462396: 0xffffffff9a1e6bc4 <-0xffffffff9a0f7323
<idle>-0 [003] d.h2. 156.462397: 0xffffffff9a0d12b4 <-0xffffffff9a0f732a
<idle>-0 [003] d.h2. 156.462397: 0xffffffff9a1458d4 <-0xffffffff9a0d12e2
<idle>-0 [003] d.h2. 156.462397: 0xffffffff9a0faed4 <-0xffffffff9a0d12e7
<idle>-0 [003] d.h2. 156.462398: 0xffffffff9a0faaf4 <-0xffffffff9a0faef2
<idle>-0 [003] d.h2. 156.462574: 0xffffffff9a0e3444 <-0xffffffff9a0d12ef
<idle>-0 [003] d.h2. 156.462575: 0xffffffff9a0e4964 <-0xffffffff9a0d12ef
<idle>-0 [003] d.h2. 156.462575: 0xffffffff9a0e3fb0 <-0xffffffff9a0e496f
Reset all CPUs when starting a boot mapped ring buffer for the first time,
and not just the online CPUs.
Fixes: 7a1d1e4b96 ("tracing/ring-buffer: Add last_boot_info file to boot instance")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
A crash happened when testing cpu hotplug with respect to the memory
mapped ring buffers. It was assumed that the hot plug code was adding a
per CPU buffer that was already created that caused the crash. The real
problem was due to ref counting and was fixed by commit 2cf9733891
("ring-buffer: Fix refcount setting of boot mapped buffers").
When a per CPU buffer is created, it will not be created again even with
CPU hotplug, so the fix to not use CPU hotplug was a red herring. In fact,
it caused only the boot CPU buffer to be created, leaving the other CPU
per CPU buffers disabled.
Revert that change as it was not the culprit of the fix it was intended to
be.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241113230839.6c03640f@gandalf.local.home
Fixes: 912da2c384 ("ring-buffer: Do not have boot mapped buffers hook to CPU hotplug")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
* arm64/for-next/perf:
perf: Switch back to struct platform_driver::remove()
perf: arm_pmuv3: Add support for Samsung Mongoose PMU
dt-bindings: arm: pmu: Add Samsung Mongoose core compatible
perf/dwc_pcie: Fix typos in event names
perf/dwc_pcie: Add support for Ampere SoCs
ARM: pmuv3: Add missing write_pmuacr()
perf/marvell: Marvell PEM performance monitor support
perf/arm_pmuv3: Add PMUv3.9 per counter EL0 access control
perf/dwc_pcie: Convert the events with mixed case to lowercase
perf/cxlpmu: Support missing events in 3.1 spec
perf: imx_perf: add support for i.MX91 platform
dt-bindings: perf: fsl-imx-ddr: Add i.MX91 compatible
drivers perf: remove unused field pmu_node
* for-next/gcs: (42 commits)
: arm64 Guarded Control Stack user-space support
kselftest/arm64: Fix missing printf() argument in gcs/gcs-stress.c
arm64/gcs: Fix outdated ptrace documentation
kselftest/arm64: Ensure stable names for GCS stress test results
kselftest/arm64: Validate that GCS push and write permissions work
kselftest/arm64: Enable GCS for the FP stress tests
kselftest/arm64: Add a GCS stress test
kselftest/arm64: Add GCS signal tests
kselftest/arm64: Add test coverage for GCS mode locking
kselftest/arm64: Add a GCS test program built with the system libc
kselftest/arm64: Add very basic GCS test program
kselftest/arm64: Always run signals tests with GCS enabled
kselftest/arm64: Allow signals tests to specify an expected si_code
kselftest/arm64: Add framework support for GCS to signal handling tests
kselftest/arm64: Add GCS as a detected feature in the signal tests
kselftest/arm64: Verify the GCS hwcap
arm64: Add Kconfig for Guarded Control Stack (GCS)
arm64/ptrace: Expose GCS via ptrace and core files
arm64/signal: Expose GCS state in signal frames
arm64/signal: Set up and restore the GCS context for signal handlers
arm64/mm: Implement map_shadow_stack()
...
* for-next/probes:
: Various arm64 uprobes/kprobes cleanups
arm64: insn: Simulate nop instruction for better uprobe performance
arm64: probes: Remove probe_opcode_t
arm64: probes: Cleanup kprobes endianness conversions
arm64: probes: Move kprobes-specific fields
arm64: probes: Fix uprobes for big-endian kernels
arm64: probes: Fix simulate_ldr*_literal()
arm64: probes: Remove broken LDR (literal) uprobe support
* for-next/asm-offsets:
: arm64 asm-offsets.c cleanup (remove unused offsets)
arm64: asm-offsets: remove PREEMPT_DISABLE_OFFSET
arm64: asm-offsets: remove DMA_{TO,FROM}_DEVICE
arm64: asm-offsets: remove VM_EXEC and PAGE_SZ
arm64: asm-offsets: remove MM_CONTEXT_ID
arm64: asm-offsets: remove COMPAT_{RT_,SIGFRAME_REGS_OFFSET
arm64: asm-offsets: remove VMA_VM_*
arm64: asm-offsets: remove TSK_ACTIVE_MM
* for-next/tlb:
: TLB flushing optimisations
arm64: optimize flush tlb kernel range
arm64: tlbflush: add __flush_tlb_range_limit_excess()
* for-next/misc:
: Miscellaneous patches
arm64: tls: Fix context-switching of tpidrro_el0 when kpti is enabled
arm64/ptrace: Clarify documentation of VL configuration via ptrace
acpi/arm64: remove unnecessary cast
arm64/mm: Change protval as 'pteval_t' in map_range()
arm64: uprobes: Optimize cache flushes for xol slot
acpi/arm64: Adjust error handling procedure in gtdt_parse_timer_block()
arm64: fix .data.rel.ro size assertion when CONFIG_LTO_CLANG
arm64/ptdump: Test both PTE_TABLE_BIT and PTE_VALID for block mappings
arm64/mm: Sanity check PTE address before runtime P4D/PUD folding
arm64/mm: Drop setting PTE_TYPE_PAGE in pte_mkcont()
ACPI: GTDT: Tighten the check for the array of platform timer structures
arm64/fpsimd: Fix a typo
arm64: Expose ID_AA64ISAR1_EL1.XS to sanitised feature consumers
arm64: Return early when break handler is found on linked-list
arm64/mm: Re-organize arch_make_huge_pte()
arm64/mm: Drop _PROT_SECT_DEFAULT
arm64: Add command-line override for ID_AA64MMFR0_EL1.ECV
arm64: head: Drop SWAPPER_TABLE_SHIFT
arm64: cpufeature: add POE to cpucap_is_possible()
arm64/mm: Change pgattr_change_is_safe() arguments as pteval_t
* for-next/mte:
: Various MTE improvements
selftests: arm64: add hugetlb mte tests
hugetlb: arm64: add mte support
* for-next/sysreg:
: arm64 sysreg updates
arm64/sysreg: Update ID_AA64MMFR1_EL1 to DDI0601 2024-09
* for-next/stacktrace:
: arm64 stacktrace improvements
arm64: preserve pt_regs::stackframe during exec*()
arm64: stacktrace: unwind exception boundaries
arm64: stacktrace: split unwind_consume_stack()
arm64: stacktrace: report recovered PCs
arm64: stacktrace: report source of unwind data
arm64: stacktrace: move dump_backtrace() to kunwind_stack_walk()
arm64: use a common struct frame_record
arm64: pt_regs: swap 'unused' and 'pmr' fields
arm64: pt_regs: rename "pmr_save" -> "pmr"
arm64: pt_regs: remove stale big-endian layout
arm64: pt_regs: assert pt_regs is a multiple of 16 bytes
* for-next/hwcap3:
: Add AT_HWCAP3 support for arm64 (also wire up AT_HWCAP4)
arm64: Support AT_HWCAP3
binfmt_elf: Wire up AT_HWCAP3 at AT_HWCAP4
* for-next/kselftest: (30 commits)
: arm64 kselftest fixes/cleanups
kselftest/arm64: Try harder to generate different keys during PAC tests
kselftest/arm64: Don't leak pipe fds in pac.exec_sign_all()
kselftest/arm64: Corrupt P0 in the irritator when testing SSVE
kselftest/arm64: Add FPMR coverage to fp-ptrace
kselftest/arm64: Expand the set of ZA writes fp-ptrace does
kselftets/arm64: Use flag bits for features in fp-ptrace assembler code
kselftest/arm64: Enable build of PAC tests with LLVM=1
kselftest/arm64: Check that SVCR is 0 in signal handlers
kselftest/arm64: Fix printf() compiler warnings in the arm64 syscall-abi.c tests
kselftest/arm64: Fix printf() warning in the arm64 MTE prctl() test
kselftest/arm64: Fix printf() compiler warnings in the arm64 fp tests
kselftest/arm64: Fix build with stricter assemblers
kselftest/arm64: Test signal handler state modification in fp-stress
kselftest/arm64: Provide a SIGUSR1 handler in the kernel mode FP stress test
kselftest/arm64: Implement irritators for ZA and ZT
kselftest/arm64: Remove unused ADRs from irritator handlers
kselftest/arm64: Correct misleading comments on fp-stress irritators
kselftest/arm64: Poll less often while waiting for fp-stress children
kselftest/arm64: Increase frequency of signal delivery in fp-stress
kselftest/arm64: Fix encoding for SVE B16B16 test
...
* for-next/crc32:
: Optimise CRC32 using PMULL instructions
arm64/crc32: Implement 4-way interleave using PMULL
arm64/crc32: Reorganize bit/byte ordering macros
arm64/lib: Handle CRC-32 alternative in C code
* for-next/guest-cca:
: Support for running Linux as a guest in Arm CCA
arm64: Document Arm Confidential Compute
virt: arm-cca-guest: TSM_REPORT support for realms
arm64: Enable memory encrypt for Realms
arm64: mm: Avoid TLBI when marking pages as valid
arm64: Enforce bounce buffers for realm DMA
efi: arm64: Map Device with Prot Shared
arm64: rsi: Map unprotected MMIO as decrypted
arm64: rsi: Add support for checking whether an MMIO is protected
arm64: realm: Query IPA size from the RMM
arm64: Detect if in a realm and set RIPAS RAM
arm64: rsi: Add RSI definitions
* for-next/haft:
: Support for arm64 FEAT_HAFT
arm64: pgtable: Warn unexpected pmdp_test_and_clear_young()
arm64: Enable ARCH_HAS_NONLEAF_PMD_YOUNG
arm64: Add support for FEAT_HAFT
arm64: setup: name 'tcr2' register
arm64/sysreg: Update ID_AA64MMFR1_EL1 register
* for-next/scs:
: Dynamic shadow call stack fixes
arm64/scs: Drop unused prototype __pi_scs_patch_vmlinux()
arm64/scs: Deal with 64-bit relative offsets in FDE frames
arm64/scs: Fix handling of DWARF augmentation data in CIE/FDE frames
- Support for stage-1 permission indirection (FEAT_S1PIE) and
permission overlays (FEAT_S1POE), including nested virt + the
emulated page table walker
- Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This call
was introduced in PSCIv1.3 as a mechanism to request hibernation,
similar to the S4 state in ACPI
- Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
part of it, introduce trivial initialization of the host's MPAM
context so KVM can use the corresponding traps
- PMU support under nested virtualization, honoring the guest
hypervisor's trap configuration and event filtering when running a
nested guest
- Fixes to vgic ITS serialization where stale device/interrupt table
entries are not zeroed when the mapping is invalidated by the VM
- Avoid emulated MMIO completion if userspace has requested synchronous
external abort injection
- Various fixes and cleanups affecting pKVM, vCPU initialization, and
selftests
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Merge tag 'kvmarm-6.13' of https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 changes for 6.13, part #1
- Support for stage-1 permission indirection (FEAT_S1PIE) and
permission overlays (FEAT_S1POE), including nested virt + the
emulated page table walker
- Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This call
was introduced in PSCIv1.3 as a mechanism to request hibernation,
similar to the S4 state in ACPI
- Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
part of it, introduce trivial initialization of the host's MPAM
context so KVM can use the corresponding traps
- PMU support under nested virtualization, honoring the guest
hypervisor's trap configuration and event filtering when running a
nested guest
- Fixes to vgic ITS serialization where stale device/interrupt table
entries are not zeroed when the mapping is invalidated by the VM
- Avoid emulated MMIO completion if userspace has requested synchronous
external abort injection
- Various fixes and cleanups affecting pKVM, vCPU initialization, and
selftests
Previously any PMU overflow interrupt that fired while a VCPU was
loaded was recorded as a guest event whether it truly was or not. This
resulted in nonsense perf recordings that did not honor
perf_event_attr.exclude_guest and recorded guest IPs where it should
have recorded host IPs.
Rework the sampling logic to only record guest samples for events with
exclude_guest = 0. This way any host-only events with exclude_guest
set will never see unexpected guest samples. The behaviour of events
with exclude_guest = 0 is unchanged.
Note that events configured to sample both host and guest may still
misattribute a PMI that arrived in the host as a guest event depending
on KVM arch and vendor behavior.
Signed-off-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20241113190156.2145593-6-coltonlewis@google.com
For clarity, rename the arch-specific definitions of these functions
to perf_arch_* to denote they are arch-specifc. Define the
generic-named functions in one place where they can call the
arch-specific ones as needed.
Signed-off-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Acked-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Acked-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20241113190156.2145593-3-coltonlewis@google.com
Introduce range_tree data structure and use it in bpf arena to track
ranges of allocated pages. range_tree is a large bitmap that is
implemented as interval tree plus rbtree. The contiguous sequence of
bits represents unallocated pages.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20241108025616.17625-2-alexei.starovoitov@gmail.com
Cross-merge bpf fixes after downstream PR.
In particular to bring the fix in
commit aa30eb3260 ("bpf: Force checkpoint when jmp history is too long").
The follow up verifier work depends on it.
And the fix in
commit 6801cf7890 ("selftests/bpf: Use -4095 as the bad address for bits iterator").
It's fixing instability of BPF CI on s390 arch.
No conflicts.
Adjacent changes in:
Auto-merging arch/Kconfig
Auto-merging kernel/bpf/helpers.c
Auto-merging kernel/bpf/memalloc.c
Auto-merging kernel/bpf/verifier.c
Auto-merging mm/slab_common.c
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
seq_printf() is more expensive than seq_put_decimal_ull_width() due to the
format string parsing costs.
Profiling on a x86 8-core system indicates seq_printf() takes ~47% samples
of show_interrupts(). Replacing it with seq_put_decimal_ull_width() yields
almost 30% performance gain.
[ tglx: Massaged changelog and fixed up coding style ]
Signed-off-by: David Wang <00107082@163.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241108160717.9547-1-00107082@163.com
Without kernel symbols for struct_ops trampoline, the unwinder may
produce unexpected stacktraces.
For example, the x86 ORC and FP unwinders check if an IP is in kernel
text by verifying the presence of the IP's kernel symbol. When a
struct_ops trampoline address is encountered, the unwinder stops due
to the absence of symbol, resulting in an incomplete stacktrace that
consists only of direct and indirect child functions called from the
trampoline.
The arm64 unwinder is another example. While the arm64 unwinder can
proceed across a struct_ops trampoline address, the corresponding
symbol name is displayed as "unknown", which is confusing.
Thus, add kernel symbol for struct_ops trampoline. The name is
bpf__<struct_ops_name>_<member_name>, where <struct_ops_name> is the
type name of the struct_ops, and <member_name> is the name of
the member that the trampoline is linked to.
Below is a comparison of stacktraces captured on x86 by perf record,
before and after this patch.
Before:
ffffffff8116545d __lock_acquire+0xad ([kernel.kallsyms])
ffffffff81167fcc lock_acquire+0xcc ([kernel.kallsyms])
ffffffff813088f4 __bpf_prog_enter+0x34 ([kernel.kallsyms])
After:
ffffffff811656bd __lock_acquire+0x30d ([kernel.kallsyms])
ffffffff81167fcc lock_acquire+0xcc ([kernel.kallsyms])
ffffffff81309024 __bpf_prog_enter+0x34 ([kernel.kallsyms])
ffffffffc000d7e9 bpf__tcp_congestion_ops_cong_avoid+0x3e ([kernel.kallsyms])
ffffffff81f250a5 tcp_ack+0x10d5 ([kernel.kallsyms])
ffffffff81f27c66 tcp_rcv_established+0x3b6 ([kernel.kallsyms])
ffffffff81f3ad03 tcp_v4_do_rcv+0x193 ([kernel.kallsyms])
ffffffff81d65a18 __release_sock+0xd8 ([kernel.kallsyms])
ffffffff81d65af4 release_sock+0x34 ([kernel.kallsyms])
ffffffff81f15c4b tcp_sendmsg+0x3b ([kernel.kallsyms])
ffffffff81f663d7 inet_sendmsg+0x47 ([kernel.kallsyms])
ffffffff81d5ab40 sock_write_iter+0x160 ([kernel.kallsyms])
ffffffff8149c67b vfs_write+0x3fb ([kernel.kallsyms])
ffffffff8149caf6 ksys_write+0xc6 ([kernel.kallsyms])
ffffffff8149cb5d __x64_sys_write+0x1d ([kernel.kallsyms])
ffffffff81009200 x64_sys_call+0x1d30 ([kernel.kallsyms])
ffffffff82232d28 do_syscall_64+0x68 ([kernel.kallsyms])
ffffffff8240012f entry_SYSCALL_64_after_hwframe+0x76 ([kernel.kallsyms])
Fixes: 85d33df357 ("bpf: Introduce BPF_MAP_TYPE_STRUCT_OPS")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20241112145849.3436772-4-xukuohai@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Only function pointers in a struct_ops structure can be linked to bpf
progs, so set the links count to the function pointers count, instead
of the total members count in the structure.
Suggested-by: Martin KaFai Lau <martin.lau@linux.dev>
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/r/20241112145849.3436772-3-xukuohai@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The rcu member in bpf_struct_ops_map is not used after commit
b671c2067a ("bpf: Retire the struct_ops map kvalue->refcnt.")
Remove it.
Suggested-by: Martin KaFai Lau <martin.lau@linux.dev>
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/r/20241112145849.3436772-2-xukuohai@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For struct_ops progs, whether a particular prog uses private stack
depends on prog->aux->priv_stack_requested setting before actual
insn-level verification for that prog. One particular implementation
is to piggyback on struct_ops->check_member(). The next patch has
an example for this. The struct_ops->check_member() sets
prog->aux->priv_stack_requested to be true which enables private stack
usage.
The struct_ops prog follows the same rule as kprobe/tracing progs after
function bpf_enable_priv_stack(). For example, even a struct_ops prog
requests private stack, it could still use normal kernel stack if
the stack size is small (< 64 bytes).
Similar to tracing progs, nested same cpu same prog run will be skipped.
A field (recursion_detected()) is added to bpf_prog_aux structure.
If bpf_prog->aux->recursion_detected is implemented by the struct_ops
subsystem and nested same cpu/prog happens, the function will be
triggered to report an error, collect related info, etc.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20241112163933.2224962-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
If private stack is used by any subprog, set that subprog
prog->aux->jits_use_priv_stack to be true so later jit can allocate
private stack for that subprog properly.
Also set env->prog->aux->jits_use_priv_stack to be true if
any subprog uses private stack. This is a use case for a
single main prog (no subprogs) to use private stack, and
also a use case for later struct-ops progs where
env->prog->aux->jits_use_priv_stack will enable recursion
check if any subprog uses private stack.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20241112163912.2224007-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Private stack will be allocated with percpu allocator in jit time.
To avoid complexity at runtime, only one copy of private stack is
available per cpu per prog. So runtime recursion check is necessary
to avoid stack corruption.
Current private stack only supports kprobe/perf_event/tp/raw_tp
which has recursion check in the kernel, and prog types that use
bpf trampoline recursion check. For trampoline related prog types,
currently only tracing progs have recursion checking.
To avoid complexity, all async_cb subprogs use normal kernel stack
including those subprogs used by both main prog subtree and async_cb
subtree. Any prog having tail call also uses kernel stack.
To avoid jit penalty with private stack support, a subprog stack
size threshold is set such that only if the stack size is no less
than the threshold, private stack is supported. The current threshold
is 64 bytes. This avoids jit penality if the stack usage is small.
A useless 'continue' is also removed from a loop in func
check_max_stack_depth().
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20241112163907.2223839-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
If srcu_read_lock_lite() is used on a given srcu_struct structure, then
the grace-period processing must do synchronize_rcu() instead of smp_mb()
between the scans of the ->srcu_unlock_count[] and ->srcu_lock_count[]
counters. Currently, it does that by testing the SRCU_READ_FLAVOR_LITE
bit of the ->srcu_reader_flavor mask, which works well. But only if
the CPU running that srcu_struct structure's grace period has previously
executed srcu_read_lock_lite(), which might not be the case, especially
just after that srcu_struct structure has been created and initialized.
This commit therefore updates the srcu_readers_unlock_idx() function
to OR together the ->srcu_reader_flavor masks from all CPUs, and
then make the srcu_readers_active_idx_check() function that test the
SRCU_READ_FLAVOR_LITE bit in the resulting mask.
Note that the srcu_readers_unlock_idx() function is already scanning all
the CPUs to sum up the ->srcu_unlock_count[] fields and that this is on
the grace-period slow path, hence no concerns about the small amount of
extra work.
Reported-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Closes: https://lore.kernel.org/all/d07e8f4a-d5ff-4c8e-8e61-50db285c57e9@amd.com/
Fixes: c0f08d6b5a61 ("srcu: Add srcu_read_lock_lite() and srcu_read_unlock_lite()")
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
If a CPU runs throughout the stalled grace period without passing
through a quiescent state, RCU priority boosting cannot help.
The rcu_torture_boost_failed() function therefore prints a message
flagging the first such CPU. However, if the stall was instead due to
(for example) RCU's grace-period kthread being starved of CPU, there will
be no such CPU, causing rcu_check_boost_fail() to instead pass back -1
through its cpup CPU-pointer parameter.
Therefore, the current message complains about a mythical CPU -1.
This commit therefore checks for this situation, and notes that all CPUs
have passed through a quiescent state.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit adds a guest_os_delay module parameter that extends warm-up
and cool-down the specified number of seconds before and after the series
of test runs. This allows the data-collection intervals from any given
rcuscale guest OSes to line up with active periods in the other rcuscale
guest OSes, and also allows the thermal warm-up period required to obtain
consistent results from one test to the next.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
The current affinity check works fine until there are more reader
processes than CPUs, at which point the affinity check is looking for
non-existent CPUs. This commit therefore applies the same modulus to
the check as is present in the set_cpus_allowed_ptr() call.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Currently, running rcutorture test with torture_type=rcu fwd_progress=8
n_barrier_cbs=8 nocbs_nthreads=8 nocbs_toggle=100 onoff_interval=60
test_boost=2, will trigger the following warning:
WARNING: CPU: 19 PID: 100 at kernel/rcu/tree_nocb.h:1061 rcu_nocb_rdp_deoffload+0x292/0x2a0
RIP: 0010:rcu_nocb_rdp_deoffload+0x292/0x2a0
Call Trace:
<TASK>
? __warn+0x7e/0x120
? rcu_nocb_rdp_deoffload+0x292/0x2a0
? report_bug+0x18e/0x1a0
? handle_bug+0x3d/0x70
? exc_invalid_op+0x18/0x70
? asm_exc_invalid_op+0x1a/0x20
? rcu_nocb_rdp_deoffload+0x292/0x2a0
rcu_nocb_cpu_deoffload+0x70/0xa0
rcu_nocb_toggle+0x136/0x1c0
? __pfx_rcu_nocb_toggle+0x10/0x10
kthread+0xd1/0x100
? __pfx_kthread+0x10/0x10
ret_from_fork+0x2f/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
CPU0 CPU2 CPU3
//rcu_nocb_toggle //nocb_cb_wait //rcutorture
// deoffload CPU1 // process CPU1's rdp
rcu_barrier()
rcu_segcblist_entrain()
rcu_segcblist_add_len(1);
// len == 2
// enqueue barrier
// callback to CPU1's
// rdp->cblist
rcu_do_batch()
// invoke CPU1's rdp->cblist
// callback
rcu_barrier_callback()
rcu_barrier()
mutex_lock(&rcu_state.barrier_mutex);
// still see len == 2
// enqueue barrier callback
// to CPU1's rdp->cblist
rcu_segcblist_entrain()
rcu_segcblist_add_len(1);
// len == 3
// decrement len
rcu_segcblist_add_len(-2);
kthread_parkme()
// CPU1's rdp->cblist len == 1
// Warn because there is
// still a pending barrier
// trigger warning
WARN_ON_ONCE(rcu_segcblist_n_cbs(&rdp->cblist));
cpus_read_unlock();
// wait CPU1 to comes online and
// invoke barrier callback on
// CPU1 rdp's->cblist
wait_for_completion(&rcu_state.barrier_completion);
// deoffload CPU4
cpus_read_lock()
rcu_barrier()
mutex_lock(&rcu_state.barrier_mutex);
// block on barrier_mutex
// wait rcu_barrier() on
// CPU3 to unlock barrier_mutex
// but CPU3 unlock barrier_mutex
// need to wait CPU1 comes online
// when CPU1 going online will block on cpus_write_lock
The above scenario will not only trigger a WARN_ON_ONCE(), but also
trigger a deadlock.
Thanks to nocb locking, a second racing rcu_barrier() on an offline CPU
will either observe the decremented callback counter down to 0 and spare
the callback enqueue, or rcuo will observe the new callback and keep
rdp->nocb_cb_sleep to false.
Therefore check rdp->nocb_cb_sleep before parking to make sure no
further rcu_barrier() is waiting on the rdp.
Fixes: 1fcb932c8b ("rcu/nocb: Simplify (de-)offloading state machine")
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
KCSAN reports a data race when access the krcp->monitor_work.timer.expires
variable in the schedule_delayed_monitor_work() function:
<snip>
BUG: KCSAN: data-race in __mod_timer / kvfree_call_rcu
read to 0xffff888237d1cce8 of 8 bytes by task 10149 on cpu 1:
schedule_delayed_monitor_work kernel/rcu/tree.c:3520 [inline]
kvfree_call_rcu+0x3b8/0x510 kernel/rcu/tree.c:3839
trie_update_elem+0x47c/0x620 kernel/bpf/lpm_trie.c:441
bpf_map_update_value+0x324/0x350 kernel/bpf/syscall.c:203
generic_map_update_batch+0x401/0x520 kernel/bpf/syscall.c:1849
bpf_map_do_batch+0x28c/0x3f0 kernel/bpf/syscall.c:5143
__sys_bpf+0x2e5/0x7a0
__do_sys_bpf kernel/bpf/syscall.c:5741 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5739 [inline]
__x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5739
x64_sys_call+0x2625/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:322
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
write to 0xffff888237d1cce8 of 8 bytes by task 56 on cpu 0:
__mod_timer+0x578/0x7f0 kernel/time/timer.c:1173
add_timer_global+0x51/0x70 kernel/time/timer.c:1330
__queue_delayed_work+0x127/0x1a0 kernel/workqueue.c:2523
queue_delayed_work_on+0xdf/0x190 kernel/workqueue.c:2552
queue_delayed_work include/linux/workqueue.h:677 [inline]
schedule_delayed_monitor_work kernel/rcu/tree.c:3525 [inline]
kfree_rcu_monitor+0x5e8/0x660 kernel/rcu/tree.c:3643
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310
worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391
kthread+0x1d1/0x210 kernel/kthread.c:389
ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 56 Comm: kworker/u8:4 Not tainted 6.12.0-rc2-syzkaller-00050-g5b7c893ed5ed #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events_unbound kfree_rcu_monitor
<snip>
kfree_rcu_monitor() rearms the work if a "krcp" has to be still
offloaded and this is done without holding krcp->lock, whereas
the kvfree_call_rcu() holds it.
Fix it by acquiring the "krcp->lock" for kfree_rcu_monitor() so
both functions do not race anymore.
Reported-by: syzbot+061d370693bdd99f9d34@syzkaller.appspotmail.com
Link: https://lore.kernel.org/lkml/ZxZ68KmHDQYU0yfD@pc636/T/
Fixes: 8fc5494ad5 ("rcu/kvfree: Move need_offload_krc() out of krcp->lock")
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Code after the return statement is dead. Enable preemption before
returning from srcu_drive_gp().
This will be important when/if PREEMPT_AUTO (lazy resched) gets merged.
Fixes: 65b4a59557 ("srcu: Make Tiny SRCU explicitly disable preemption")
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit removes the open-coded one-byte cmpxchg() emulation from
rcu_trc_cmpxchg_need_qs(), replacing it with just cmpxchg() given the
latter's new-found ability to handle single-byte arguments across all
architectures.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit tests the ->start_poll() and ->start_poll_full() functions
with interrupts disabled, but only for RCU variants setting the
->start_poll_irqsoff flag.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
The header comment for both start_poll_synchronize_rcu() and
start_poll_synchronize_rcu_full() state that interrupts must be enabled
when calling these two functions, and there is a lockdep assertion in
start_poll_synchronize_rcu_common() enforcing this restriction. However,
there is no need for this restrictions, as can be seen in call_rcu(),
which does wakeups when interrupts are disabled.
This commit therefore removes the lockdep assertion and the comments.
Reported-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
There are now architectures for which all deep-idle and entry-exit
functions are properly inlined or marked noinstr. Such architectures do
not need synchronize_rcu_tasks_rude(), or will not once RCU Tasks has
been modified to pay attention to idle tasks. This commit therefore
allows a CONFIG_ARCH_HAS_NOINSTR_MARKINGS Kconfig option to turn
synchronize_rcu_tasks_rude() into a no-op.
To facilitate testing, kernels built by rcutorture scripting will enable
RCU Tasks Trace even on systems that do not need it.
[ paulmck: Apply Peter Zijlstra feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
The RCU_NOCB_CPU help text currently fails to mention rcuog kthreads,
so this commit adds this information.
Reported-by: Olivier Langlois <olivier@trillion01.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
sizeof(unsigned long) * 8 is the number of bits in an unsigned long
variable, replace it with BITS_PER_LONG macro to make it simpler.
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This silences the following coccinelle warning:
WARNING: sum of probable bitmasks, consider |
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Ensure sugov_eas_rebuild_sd() is always called when sugov_init()
succeeds. The out goto initialized sugov without forcing the rebuild.
Previously the missing call to sugov_eas_rebuild_sd() could lead to EAS
not being enabled on boot when it should have been, because it requires
all policies to be controlled by schedutil while they might not have
been initialized yet.
Fixes: e7a1b32e43 ("cpufreq: Rebuild sched-domains when removing cpufreq driver")
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/35e572d9-1152-406a-9e34-2525f7548af9@arm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently the cpuset code uses group_subsys_on_dfl() to check if we
are running with cgroup v2. If CONFIG_CPUSETS_V1 isn't set, there is
really no need to do this check and we can optimize out some of the
unneeded v1 specific code paths. Introduce a new cpuset_v2() and use it
to replace the cgroup_subsys_on_dfl() check to further optimize the
code.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Since commit ff0ce721ec ("cgroup/cpuset: Eliminate unncessary
sched domains rebuilds in hotplug"), there is only one
rebuild_sched_domains_locked() call per hotplug operation. However,
writing to the various cpuset control files may still casue more than
one rebuild_sched_domains_locked() call to happen in some cases.
Juri had found that two rebuild_sched_domains_locked() calls in
update_prstate(), one from update_cpumasks_hier() and another one from
update_partition_sd_lb() could cause cpuset partition to be created
with null total_bw for DL tasks. IOW, DL tasks may not be scheduled
correctly in such a partition.
A sample command sequence that can reproduce null total_bw is as
follows.
# echo Y >/sys/kernel/debug/sched/verbose
# echo +cpuset >/sys/fs/cgroup/cgroup.subtree_control
# mkdir /sys/fs/cgroup/test
# echo 0-7 > /sys/fs/cgroup/test/cpuset.cpus
# echo 6-7 > /sys/fs/cgroup/test/cpuset.cpus.exclusive
# echo root >/sys/fs/cgroup/test/cpuset.cpus.partition
Fix this double rebuild_sched_domains_locked() calls problem
by replacing existing calls with cpuset_force_rebuild() except
the rebuild_sched_domains_cpuslocked() call at the end of
cpuset_handle_hotplug(). Checking of the force_sd_rebuild flag is
now done at the end of cpuset_write_resmask() and update_prstate()
to determine if rebuild_sched_domains_locked() should be called or not.
The cpuset v1 code can still call rebuild_sched_domains_locked()
directly as double rebuild_sched_domains_locked() calls is not possible.
Reported-by: Juri Lelli <juri.lelli@redhat.com>
Closes: https://lore.kernel.org/lkml/ZyuUcJDPBln1BK1Y@jlelli-thinkpadt14gen4.remote.csb/
Signed-off-by: Waiman Long <longman@redhat.com>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Revert commit 3ae0b77321 ("cgroup/cpuset: Allow suppression of sched
domain rebuild in update_cpumasks_hier()") to allow for an alternative
way to suppress unnecessary rebuild_sched_domains_locked() calls in
update_cpumasks_hier() and elsewhere in a following commit.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The check on field->field being true is handled as the first check
on the cascaded if statement, so the later checks on field->field
are redundant because this clause has already been handled. Since
this later check is redundant, just remove it.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241107120530.18728-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit creates a new srcu-lite option for the refscale.scale_type
module parameter that selects srcu_read_lock_lite() and
srcu_read_unlock_lite().
[ paulmck: Apply Dan Carpenter feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit causes bit 0x4 of rcutorture.reader_flavor to select the new
srcu_read_lock_lite() and srcu_read_unlock_lite() functions.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit adds an rcutorture.reader_flavor parameter whose bits
correspond to reader flavors. For example, SRCU's readers are 0x1 for
normal and 0x2 for NMI-safe.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit prepares for testing of multiple SRCU reader flavors by
expanding RCUTORTURE_RDR_MASK_1 and RCUTORTURE_RDR_MASK_2 from a single
bit to eight bits, allowing them to accommodate the return values from
multiple calls to srcu_read_lock*(). This will in turn permit better
testing coverage for these SRCU reader flavors, including testing of
the diagnostics for inproper use of mixed reader flavors.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit moves __srcu_read_lock_lite() and __srcu_read_unlock_lite()
into include/linux/srcu.h and marks them "static inline" so that they
can be inlined into srcu_read_lock_lite() and srcu_read_unlock_lite(),
respectively. They are not hand-inlined due to Tree SRCU and Tiny SRCU
having different implementations.
The earlier removal of smp_mb() combined with the inlining produce
significant single-percentage performance wins.
Link: https://lore.kernel.org/all/CAEf4BzYgiNmSb=ZKQ65tm6nJDi1UX2Gq26cdHSH1mPwXJYZj5g@mail.gmail.com/
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This patch adds srcu_read_lock_lite() and srcu_read_unlock_lite(), which
dispense with the read-side smp_mb() but also are restricted to code
regions that RCU is watching. If a given srcu_struct structure uses
srcu_read_lock_lite() and srcu_read_unlock_lite(), it is not permitted
to use any other SRCU read-side marker, before, during, or after.
Another price of light-weight readers is heavier weight grace periods.
Such readers mean that SRCU grace periods on srcu_struct structures
used by light-weight readers will incur at least two calls to
synchronize_rcu(). In addition, normal SRCU grace periods for
light-weight-reader srcu_struct structures never auto-expedite.
Note that expedited SRCU grace periods for light-weight-reader
srcu_struct structures still invoke synchronize_rcu(), not
synchronize_srcu_expedited(). Something about wishing to keep
the IPIs down to a dull roar.
The srcu_read_lock_lite() and srcu_read_unlock_lite() functions may not
(repeat, *not*) be used from NMI handlers, but if this is needed, an
additional flavor of SRCU reader can be added by some future commit.
[ paulmck: Apply Alexei Starovoitov expediting feedback. ]
[ paulmck: Apply kernel test robot feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: kernel test robot <oliver.sang@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit creates SRCU_READ_FLAVOR_NORMAL and SRCU_READ_FLAVOR_NMI
C-preprocessor macros for srcu_read_lock() and srcu_read_lock_nmisafe(),
respectively. These replace the old true/false values that were
previously passed to srcu_check_read_flavor(). In addition, the
srcu_check_read_flavor() function itself requires a bit of rework to
handle bitmasks instead of true/false values.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Currently, there are only two flavors of readers, normal and NMI-safe.
Very straightforward state updates suffice to check for erroneous
mixing of reader flavors on a given srcu_struct structure. This commit
upgrades the checking in preparation for the addition of light-weight
(as in memory-barrier-free) readers.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Currently, there are only two flavors of readers, normal and NMI-safe.
A number of fields, functions, and types reflect this restriction.
This renaming-only commit prepares for the addition of light-weight
(as in memory-barrier-free) readers. OK, OK, there is also a drive-by
white-space fixeup!
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
As Documentation/filesystems/sysfs.rst suggested, show() should only use
sysfs_emit() or sysfs_emit_at() when formatting the value to be returned
to user space.
No functional change intended.
Link: https://lkml.kernel.org/r/20241105094941.33739-1-zhangguopeng@kylinos.cn
Signed-off-by: zhangguopeng <zhangguopeng@kylinos.cn>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Fabio Estevam <festevam@denx.de>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "add detect count for hung tasks", v2.
This patchset adds a counter, hung_task_detect_count, to track the number
of times hung tasks are detected.
IHMO, hung tasks are a critical metric. Currently, we detect them by
periodically parsing dmesg. However, this method isn't as user-friendly
as using a counter.
Sometimes, a short-lived issue with NIC or hard drive can quickly decrease
the hung_task_warnings to zero. Without warnings, we must directly access
the node to ensure that there are no more hung tasks and that the system
has recovered. After all, load average alone cannot provide a clear
picture.
Once this counter is in place, in a high-density deployment pattern, we
plan to set hung_task_timeout_secs to a lower number to improve stability,
even though this might result in false positives. And then we can set a
time-based threshold: if hung tasks last beyond this duration, we will
automatically migrate containers to other nodes. Based on past
experience, this approach could help avoid many production disruptions.
Moreover, just like other important events such as OOM that already have
counters, having a dedicated counter for hung tasks makes sense ;)
This patch (of 2):
This commit adds a counter, hung_task_detect_count, to track the number of
times hung tasks are detected.
IHMO, hung tasks are a critical metric. Currently, we detect them by
periodically parsing dmesg. However, this method isn't as user-friendly as
using a counter.
Sometimes, a short-lived issue with NIC or hard drive can quickly decrease
the hung_task_warnings to zero. Without warnings, we must directly access
the node to ensure that there are no more hung tasks and that the system
has recovered. After all, load average alone cannot provide a clear
picture.
Once this counter is in place, in a high-density deployment pattern, we
plan to set hung_task_timeout_secs to a lower number to improve stability,
even though this might result in false positives. And then we can set a
time-based threshold: if hung tasks last beyond this duration, we will
automatically migrate containers to other nodes. Based on past experience,
this approach could help avoid many production disruptions.
Moreover, just like other important events such as OOM that already have
counters, having a dedicated counter for hung tasks makes sense.
[ioworker0@gmail.com: proc_doulongvec_minmax instead of proc_dointvec]
Link: https://lkml.kernel.org/r/20241101114833.8377-1-ioworker0@gmail.com
Link: https://lkml.kernel.org/r/20241027120747.42833-1-ioworker0@gmail.com
Link: https://lkml.kernel.org/r/20241027120747.42833-2-ioworker0@gmail.com
Signed-off-by: Mingzhe Yang <mingzhe.yang@ly.com>
Signed-off-by: Lance Yang <ioworker0@gmail.com>
Cc: Bang Li <libang.li@antgroup.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Cun <cunhuang@tencent.com>
Cc: Joel Granados <j.granados@samsung.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Siddle <jsiddle@redhat.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Weißschuh <linux@weissschuh.net>
Cc: Yongliang Gao <leonylgao@tencent.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
- The fair sched class currently has a bug where its balance() returns true
telling the sched core that it has tasks to run but then NULL from
pick_task(). This makes sched core call sched_ext's pick_task() without
preceding balance() which can lead to stalls in partial mode. For now,
work around by detecting the condition and forcing the CPU to go through
another scheduling cycle.
- Add a missing newline to an error message and fix drgn introspection tool
which went out of sync.
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Merge tag 'sched_ext-for-6.12-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Pull sched_ext fixes from Tejun Heo:
- The fair sched class currently has a bug where its balance() returns
true telling the sched core that it has tasks to run but then NULL
from pick_task(). This makes sched core call sched_ext's pick_task()
without preceding balance() which can lead to stalls in partial mode.
For now, work around by detecting the condition and forcing the CPU
to go through another scheduling cycle.
- Add a missing newline to an error message and fix drgn introspection
tool which went out of sync.
* tag 'sched_ext-for-6.12-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
sched_ext: Handle cases where pick_task_scx() is called without preceding balance_scx()
sched_ext: Update scx_show_state.py to match scx_ops_bypass_depth's new type
sched_ext: Add a missing newline at the end of an error message
* kvm-arm64/psci-1.3:
: PSCI v1.3 support, courtesy of David Woodhouse
:
: Bump KVM's PSCI implementation up to v1.3, with the added bonus of
: implementing the SYSTEM_OFF2 call. Like other system-scoped PSCI calls,
: this gets relayed to userspace for further processing with a new
: KVM_SYSTEM_EVENT_SHUTDOWN flag.
:
: As an added bonus, implement client-side support for hibernation with
: the SYSTEM_OFF2 call.
arm64: Use SYSTEM_OFF2 PSCI call to power off for hibernate
KVM: arm64: nvhe: Pass through PSCI v1.3 SYSTEM_OFF2 call
KVM: selftests: Add test for PSCI SYSTEM_OFF2
KVM: arm64: Add support for PSCI v1.2 and v1.3
KVM: arm64: Add PSCI v1.3 SYSTEM_OFF2 function for hibernation
firmware/psci: Add definitions for PSCI v1.3 specification
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
In sched_ext API, a repeatedly reported pain point is the overuse of the
verb "dispatch" and confusion around "consume":
- ops.dispatch()
- scx_bpf_dispatch[_vtime]()
- scx_bpf_consume()
- scx_bpf_dispatch[_vtime]_from_dsq*()
This overloading of the term is historical. Originally, there were only
built-in DSQs and moving a task into a DSQ always dispatched it for
execution. Using the verb "dispatch" for the kfuncs to move tasks into these
DSQs made sense.
Later, user DSQs were added and scx_bpf_dispatch[_vtime]() updated to be
able to insert tasks into any DSQ. The only allowed DSQ to DSQ transfer was
from a non-local DSQ to a local DSQ and this operation was named "consume".
This was already confusing as a task could be dispatched to a user DSQ from
ops.enqueue() and then the DSQ would have to be consumed in ops.dispatch().
Later addition of scx_bpf_dispatch_from_dsq*() made the confusion even worse
as "dispatch" in this context meant moving a task to an arbitrary DSQ from a
user DSQ.
Clean up the API with the following renames:
1. scx_bpf_dispatch[_vtime]() -> scx_bpf_dsq_insert[_vtime]()
2. scx_bpf_consume() -> scx_bpf_dsq_move_to_local()
3. scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*()
This patch performs the third set of renames. Compatibility is maintained
by:
- The previous kfunc names are still provided by the kernel so that old
binaries can run. Kernel generates a warning when the old names are used.
- compat.bpf.h provides wrappers for the new names which automatically fall
back to the old names when running on older kernels. They also trigger
build error if old names are used for new builds.
- scx_bpf_dispatch[_vtime]_from_dsq*() were already wrapped in __COMPAT
macros as they were introduced during v6.12 cycle. Wrap new API in
__COMPAT macros too and trigger build errors on both __COMPAT prefixed and
naked usages of the old names.
The compat features will be dropped after v6.15.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Andrea Righi <arighi@nvidia.com>
Acked-by: Changwoo Min <changwoo@igalia.com>
Acked-by: Johannes Bechberger <me@mostlynerdless.de>
Acked-by: Giovanni Gherdovich <ggherdovich@suse.com>
Cc: Dan Schatzberg <dschatzberg@meta.com>
Cc: Ming Yang <yougmark94@gmail.com>
In sched_ext API, a repeatedly reported pain point is the overuse of the
verb "dispatch" and confusion around "consume":
- ops.dispatch()
- scx_bpf_dispatch[_vtime]()
- scx_bpf_consume()
- scx_bpf_dispatch[_vtime]_from_dsq*()
This overloading of the term is historical. Originally, there were only
built-in DSQs and moving a task into a DSQ always dispatched it for
execution. Using the verb "dispatch" for the kfuncs to move tasks into these
DSQs made sense.
Later, user DSQs were added and scx_bpf_dispatch[_vtime]() updated to be
able to insert tasks into any DSQ. The only allowed DSQ to DSQ transfer was
from a non-local DSQ to a local DSQ and this operation was named "consume".
This was already confusing as a task could be dispatched to a user DSQ from
ops.enqueue() and then the DSQ would have to be consumed in ops.dispatch().
Later addition of scx_bpf_dispatch_from_dsq*() made the confusion even worse
as "dispatch" in this context meant moving a task to an arbitrary DSQ from a
user DSQ.
Clean up the API with the following renames:
1. scx_bpf_dispatch[_vtime]() -> scx_bpf_dsq_insert[_vtime]()
2. scx_bpf_consume() -> scx_bpf_dsq_move_to_local()
3. scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*()
This patch performs the second rename. Compatibility is maintained by:
- The previous kfunc names are still provided by the kernel so that old
binaries can run. Kernel generates a warning when the old names are used.
- compat.bpf.h provides wrappers for the new names which automatically fall
back to the old names when running on older kernels. They also trigger
build error if old names are used for new builds.
The compat features will be dropped after v6.15.
v2: Comment and documentation updates.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Andrea Righi <arighi@nvidia.com>
Acked-by: Changwoo Min <changwoo@igalia.com>
Acked-by: Johannes Bechberger <me@mostlynerdless.de>
Acked-by: Giovanni Gherdovich <ggherdovich@suse.com>
Cc: Dan Schatzberg <dschatzberg@meta.com>
Cc: Ming Yang <yougmark94@gmail.com>
In sched_ext API, a repeatedly reported pain point is the overuse of the
verb "dispatch" and confusion around "consume":
- ops.dispatch()
- scx_bpf_dispatch[_vtime]()
- scx_bpf_consume()
- scx_bpf_dispatch[_vtime]_from_dsq*()
This overloading of the term is historical. Originally, there were only
built-in DSQs and moving a task into a DSQ always dispatched it for
execution. Using the verb "dispatch" for the kfuncs to move tasks into these
DSQs made sense.
Later, user DSQs were added and scx_bpf_dispatch[_vtime]() updated to be
able to insert tasks into any DSQ. The only allowed DSQ to DSQ transfer was
from a non-local DSQ to a local DSQ and this operation was named "consume".
This was already confusing as a task could be dispatched to a user DSQ from
ops.enqueue() and then the DSQ would have to be consumed in ops.dispatch().
Later addition of scx_bpf_dispatch_from_dsq*() made the confusion even worse
as "dispatch" in this context meant moving a task to an arbitrary DSQ from a
user DSQ.
Clean up the API with the following renames:
1. scx_bpf_dispatch[_vtime]() -> scx_bpf_dsq_insert[_vtime]()
2. scx_bpf_consume() -> scx_bpf_dsq_move_to_local()
3. scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*()
This patch performs the first set of renames. Compatibility is maintained
by:
- The previous kfunc names are still provided by the kernel so that old
binaries can run. Kernel generates a warning when the old names are used.
- compat.bpf.h provides wrappers for the new names which automatically fall
back to the old names when running on older kernels. They also trigger
build error if old names are used for new builds.
The compat features will be dropped after v6.15.
v2: Documentation updates.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Andrea Righi <arighi@nvidia.com>
Acked-by: Changwoo Min <changwoo@igalia.com>
Acked-by: Johannes Bechberger <me@mostlynerdless.de>
Acked-by: Giovanni Gherdovich <ggherdovich@suse.com>
Cc: Dan Schatzberg <dschatzberg@meta.com>
Cc: Ming Yang <yougmark94@gmail.com>
Logic to prevent callbacks from acquiring new references for the program
(i.e. leaving acquired references), and releasing caller references
(i.e. those acquired in parent frames) was introduced in commit
9d9d00ac29 ("bpf: Fix reference state management for synchronous callbacks").
This was necessary because back then, the verifier simulated each
callback once (that could potentially be executed N times, where N can
be zero). This meant that callbacks that left lingering resources or
cleared caller resources could do it more than once, operating on
undefined state or leaking memory.
With the fixes to callback verification in commit
ab5cfac139 ("bpf: verify callbacks as if they are called unknown number of times"),
all of this extra logic is no longer necessary. Hence, drop it as part
of this commit.
Cc: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20241109231430.2475236-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
When bpf_spin_lock was introduced originally, there was deliberation on
whether to use an array of lock IDs, but since bpf_spin_lock is limited
to holding a single lock at any given time, we've been using a single ID
to identify the held lock.
In preparation for introducing spin locks that can be taken multiple
times, introduce support for acquiring multiple lock IDs. For this
purpose, reuse the acquired_refs array and store both lock and pointer
references. We tag the entry with REF_TYPE_PTR or REF_TYPE_LOCK to
disambiguate and find the relevant entry. The ptr field is used to track
the map_ptr or btf (for bpf_obj_new allocations) to ensure locks can be
matched with protected fields within the same "allocation", i.e.
bpf_obj_new object or map value.
The struct active_lock is changed to an int as the state is part of the
acquired_refs array, and we only need active_lock as a cheap way of
detecting lock presence.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20241109231430.2475236-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
For htab of maps, when the map is removed from the htab, it may hold the
last reference of the map. bpf_map_fd_put_ptr() will invoke
bpf_map_free_id() to free the id of the removed map element. However,
bpf_map_fd_put_ptr() is invoked while holding a bucket lock
(raw_spin_lock_t), and bpf_map_free_id() attempts to acquire map_idr_lock
(spinlock_t), triggering the following lockdep warning:
=============================
[ BUG: Invalid wait context ]
6.11.0-rc4+ #49 Not tainted
-----------------------------
test_maps/4881 is trying to lock:
ffffffff84884578 (map_idr_lock){+...}-{3:3}, at: bpf_map_free_id.part.0+0x21/0x70
other info that might help us debug this:
context-{5:5}
2 locks held by test_maps/4881:
#0: ffffffff846caf60 (rcu_read_lock){....}-{1:3}, at: bpf_fd_htab_map_update_elem+0xf9/0x270
#1: ffff888149ced148 (&htab->lockdep_key#2){....}-{2:2}, at: htab_map_update_elem+0x178/0xa80
stack backtrace:
CPU: 0 UID: 0 PID: 4881 Comm: test_maps Not tainted 6.11.0-rc4+ #49
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ...
Call Trace:
<TASK>
dump_stack_lvl+0x6e/0xb0
dump_stack+0x10/0x20
__lock_acquire+0x73e/0x36c0
lock_acquire+0x182/0x450
_raw_spin_lock_irqsave+0x43/0x70
bpf_map_free_id.part.0+0x21/0x70
bpf_map_put+0xcf/0x110
bpf_map_fd_put_ptr+0x9a/0xb0
free_htab_elem+0x69/0xe0
htab_map_update_elem+0x50f/0xa80
bpf_fd_htab_map_update_elem+0x131/0x270
htab_map_update_elem+0x50f/0xa80
bpf_fd_htab_map_update_elem+0x131/0x270
bpf_map_update_value+0x266/0x380
__sys_bpf+0x21bb/0x36b0
__x64_sys_bpf+0x45/0x60
x64_sys_call+0x1b2a/0x20d0
do_syscall_64+0x5d/0x100
entry_SYSCALL_64_after_hwframe+0x76/0x7e
One way to fix the lockdep warning is using raw_spinlock_t for
map_idr_lock as well. However, bpf_map_alloc_id() invokes
idr_alloc_cyclic() after acquiring map_idr_lock, it will trigger a
similar lockdep warning because the slab's lock (s->cpu_slab->lock) is
still a spinlock.
Instead of changing map_idr_lock's type, fix the issue by invoking
htab_put_fd_value() after htab_unlock_bucket(). However, only deferring
the invocation of htab_put_fd_value() is not enough, because the old map
pointers in htab of maps can not be saved during batched deletion.
Therefore, also defer the invocation of free_htab_elem(), so these
to-be-freed elements could be linked together similar to lru map.
There are four callers for ->map_fd_put_ptr:
(1) alloc_htab_elem() (through htab_put_fd_value())
It invokes ->map_fd_put_ptr() under a raw_spinlock_t. The invocation of
htab_put_fd_value() can not simply move after htab_unlock_bucket(),
because the old element has already been stashed in htab->extra_elems.
It may be reused immediately after htab_unlock_bucket() and the
invocation of htab_put_fd_value() after htab_unlock_bucket() may release
the newly-added element incorrectly. Therefore, saving the map pointer
of the old element for htab of maps before unlocking the bucket and
releasing the map_ptr after unlock. Beside the map pointer in the old
element, should do the same thing for the special fields in the old
element as well.
(2) free_htab_elem() (through htab_put_fd_value())
Its caller includes __htab_map_lookup_and_delete_elem(),
htab_map_delete_elem() and __htab_map_lookup_and_delete_batch().
For htab_map_delete_elem(), simply invoke free_htab_elem() after
htab_unlock_bucket(). For __htab_map_lookup_and_delete_batch(), just
like lru map, linking the to-be-freed element into node_to_free list
and invoking free_htab_elem() for these element after unlock. It is safe
to reuse batch_flink as the link for node_to_free, because these
elements have been removed from the hash llist.
Because htab of maps doesn't support lookup_and_delete operation,
__htab_map_lookup_and_delete_elem() doesn't have the problem, so kept
it as is.
(3) fd_htab_map_free()
It invokes ->map_fd_put_ptr without raw_spinlock_t.
(4) bpf_fd_htab_map_update_elem()
It invokes ->map_fd_put_ptr without raw_spinlock_t.
After moving free_htab_elem() outside htab bucket lock scope, using
pcpu_freelist_push() instead of __pcpu_freelist_push() to disable
the irq before freeing elements, and protecting the invocations of
bpf_mem_cache_free() with migrate_{disable|enable} pair.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20241106063542.357743-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Placing bpf_session_run_ctx layer in between bpf_run_ctx and
bpf_uprobe_multi_run_ctx, so the session data can be retrieved
from uprobe_multi link.
Plus granting session kfuncs access to uprobe session programs.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241108134544.480660-5-jolsa@kernel.org
Adding support to attach BPF program for entry and return probe
of the same function. This is common use case which at the moment
requires to create two uprobe multi links.
Adding new BPF_TRACE_UPROBE_SESSION attach type that instructs
kernel to attach single link program to both entry and exit probe.
It's possible to control execution of the BPF program on return
probe simply by returning zero or non zero from the entry BPF
program execution to execute or not the BPF program on return
probe respectively.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241108134544.480660-4-jolsa@kernel.org
As suggested by Andrii make uprobe multi bpf programs to always return 0,
so they can't force uprobe removal.
Keeping the int return type for uprobe_prog_run, because it will be used
in following session changes.
Fixes: 89ae89f53d ("bpf: Add multi uprobe link")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241108134544.480660-3-jolsa@kernel.org
The kprobe session program can return only 0 or 1,
instruct verifier to check for that.
Fixes: 535a3692ba ("bpf: Add support for kprobe session attach")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241108134544.480660-2-jolsa@kernel.org
Introduce FORCE_CON flag to printk. The new flag will make it possible to
create a context where printk messages will never be suppressed.
This mechanism will be used in the next patch to create a force_con
context on sysrq handling, removing an existing workaround on the
loglevel global variable. The workaround existed to make sure that sysrq
header messages were sent to all consoles, but this doesn't work with
deferred messages because the loglevel might be restored to its original
value before a console flushes the messages.
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20241105-printk-loud-con-v2-1-bd3ecdf7b0e4@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Add a light version of override/revert_creds(), this should only be
used when the credentials in question will outlive the critical
section and the critical section doesn't change the ->usage of the
credentials.
Suggested-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Pick up e7ac4daeed ("mm: count zeromap read and set for swapout and
swapin") in order to move
mm: define obj_cgroup_get() if CONFIG_MEMCG is not defined
mm: zswap: modify zswap_compress() to accept a page instead of a folio
mm: zswap: rename zswap_pool_get() to zswap_pool_tryget()
mm: zswap: modify zswap_stored_pages to be atomic_long_t
mm: zswap: support large folios in zswap_store()
mm: swap: count successful large folio zswap stores in hugepage zswpout stats
mm: zswap: zswap_store_page() will initialize entry after adding to xarray.
mm: add per-order mTHP swpin counters
from mm-unstable into mm-stable.
Three affect DAMON. Lorenzo's five-patch series to address the
mmap_region error handling is here also.
Apart from that, various singletons.
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Merge tag 'mm-hotfixes-stable-2024-11-09-22-40' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"20 hotfixes, 14 of which are cc:stable.
Three affect DAMON. Lorenzo's five-patch series to address the
mmap_region error handling is here also.
Apart from that, various singletons"
* tag 'mm-hotfixes-stable-2024-11-09-22-40' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mailmap: add entry for Thorsten Blum
ocfs2: remove entry once instead of null-ptr-dereference in ocfs2_xa_remove()
signal: restore the override_rlimit logic
fs/proc: fix compile warning about variable 'vmcore_mmap_ops'
ucounts: fix counter leak in inc_rlimit_get_ucounts()
selftests: hugetlb_dio: check for initial conditions to skip in the start
mm: fix docs for the kernel parameter ``thp_anon=``
mm/damon/core: avoid overflow in damon_feed_loop_next_input()
mm/damon/core: handle zero schemes apply interval
mm/damon/core: handle zero {aggregation,ops_update} intervals
mm/mlock: set the correct prev on failure
objpool: fix to make percpu slot allocation more robust
mm/page_alloc: keep track of free highatomic
mm: resolve faulty mmap_region() error path behaviour
mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling
mm: refactor map_deny_write_exec()
mm: unconditionally close VMAs on error
mm: avoid unsafe VMA hook invocation when error arises on mmap hook
mm/thp: fix deferred split unqueue naming and locking
mm/thp: fix deferred split queue not partially_mapped
In commit 24cc57d8fa ("padata: Honor the caller's alignment in case of
chunk_size 0"), the line 'ps.chunk_size = max(ps.chunk_size, 1ul)' was
added, making 'ps.chunk_size = 1U' redundant and never executed.
Signed-off-by: Zicheng Qu <quzicheng@huawei.com>
Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
sched_ext dispatches tasks from the BPF scheduler from balance_scx() and
thus every pick_task_scx() call must be preceded by balance_scx(). While
this usually holds, due to a bug, there are cases where the fair class's
balance() returns true indicating that it has tasks to run on the CPU and
thus terminating balance() calls but fails to actually find the next task to
run when pick_task() is called. In such cases, pick_task_scx() can be called
without preceding balance_scx().
Detect this condition using SCX_RQ_BAL_PENDING flags. If detected, keep
running the previous task if possible and avoid stalling from entering idle
without balancing.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/Ztj_h5c2LYsdXYbA@slm.duckdns.org
4c30f5ce4f ("sched_ext: Implement scx_bpf_dispatch[_vtime]_from_dsq()")
added four kfuncs for dispatching while iterating. They are allowed from the
dispatch and unlocked contexts but two of the kfuncs were only added in the
dispatch section. Add missing declarations in the unlocked section.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 4c30f5ce4f ("sched_ext: Implement scx_bpf_dispatch[_vtime]_from_dsq()")
scf_handler() is used as a SMP function call. This function is always
invoked in IRQ-context even with forced-threading enabled. This function
frees memory which not allowed on PREEMPT_RT because the locking
underneath is using sleeping locks.
Add a per-CPU scf_free_pool where each SMP functions adds its memory to
be freed. This memory is then freed by scftorture_invoker() on each
iteration. On the majority of invocations the number of items is less
than five. If the thread sleeps/ gets delayed the number exceed 350 but
did not reach 400 in testing. These were the spikes during testing.
The bulk free of 64 pointers at once should improve the give-back if the
list grows. The list size is ~1.3 items per invocations.
Having one global scf_free_pool with one cleaning thread let the list
grow to over 10.000 items with 32 CPUs (again, spikes not the average)
especially if the CPU went to sleep. The per-CPU part looks like a good
compromise.
Reported-by: "Paul E. McKenney" <paulmck@kernel.org>
Closes: https://lore.kernel.org/lkml/41619255-cdc2-4573-a360-7794fc3614f7@paulmck-laptop/
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Memory allocations can not happen within regions with explicit disabled
preemption PREEMPT_RT. The problem is that the locking structures
underneath are sleeping locks.
Move the memory allocation outside of the preempt-disabled section. Keep
the GFP_ATOMIC for the allocation to behave like a "ememergncy
allocation".
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The smp_call_function() needs to be invoked with the wait flag set to
wait until scf_cleanup_handler() is done. This ensures that all SMP
function calls, that have been queued earlier, complete at this point.
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Replace "scfp->cpu % nr_cpu_ids" with "cpu". This has been computed
earlier.
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Update the comments in sched_ext_ops to clarify this table is for
a BPF scheduler and a userland scheduler should also rely on the
sched_ext_ops table through the BPF scheduler.
Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
On 2 x Intel Sapphire Rapids machines with 224 logical CPUs, a poorly
behaving BPF scheduler can live-lock the system by making multiple CPUs bang
on the same DSQ to the point where soft-lockup detection triggers before
SCX's own watchdog can take action. It also seems possible that the machine
can be live-locked enough to prevent scx_ops_helper, which is an RT task,
from running in a timely manner.
Implement scx_softlockup() which is called when three quarters of
soft-lockup threshold has passed. The function immediately enables the ops
breather and triggers an ops error to initiate ejection of the BPF
scheduler.
The previous and this patch combined enable the kernel to reliably recover
the system from live-lock conditions that can be triggered by a poorly
behaving BPF scheduler on Intel dual socket systems.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
A poorly behaving BPF scheduler can live-lock the system by e.g. incessantly
banging on the same DSQ on a large NUMA system to the point where switching
to the bypass mode can take a long time. Turning on the bypass mode requires
dequeueing and re-enqueueing currently runnable tasks, if the DSQs that they
are on are live-locked, this can take tens of seconds cascading into other
failures. This was observed on 2 x Intel Sapphire Rapids machines with 224
logical CPUs.
Inject artifical delays while the bypass mode is switching to guarantee
timely completion.
While at it, move __scx_ops_bypass_lock into scx_ops_bypass() and rename it
to bypass_lock.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Valentin Andrei <vandrei@meta.com>
Reported-by: Patrick Lu <patlu@meta.com>
Pull sched_ext/for-6.12-fixes to receive 0e7ffff1b8 ("scx: Fix raciness in
scx_ops_bypass()"). Planned updates for scx_ops_bypass() depends on it.
Signed-off-by: Tejun Heo <tj@kernel.org>
There is no reason to use a bitwise AND when checking the conditions to
enable NUMA optimization for the built-in CPU idle selection policy, so
use a logical AND instead.
Fixes: f6ce6b9493 ("sched_ext: Do not enable LLC/NUMA optimizations when domains overlap")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/lkml/20241108181753.GA2681424@thelio-3990X/
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
trace_dma_alloc_sgt_err was called with the dir and flags arguments
swapped. Fix this.
Fixes: 68b6dbf1f4 ("dma-mapping: trace more error paths")
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202410302243.1wnTlPk3-lkp@intel.com/
Signed-off-by: Christoph Hellwig <hch@lst.de>
When the LLC and NUMA domains fully overlap, enabling both optimizations
in the built-in idle CPU selection policy is redundant, as it leads to
searching for an idle CPU within the same domain twice.
Likewise, if all online CPUs are within a single LLC domain, LLC
optimization is unnecessary.
Therefore, detect overlapping domains and enable topology optimizations
only when necessary.
Moreover, rely on the online CPUs for this detection logic, instead of
using the possible CPUs.
Fixes: 860a45219b ("sched_ext: Introduce NUMA awareness to the default idle selection policy")
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
There are several places which currently open-code page_pgoff(), convert
them to call it.
Link: https://lkml.kernel.org/r/20241005200121.3231142-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When a module gets unloaded there is a possibility that some of the
allocations it made are still used and therefore the allocation tags
corresponding to these allocations are still referenced. As such, the
memory for these tags can't be freed. This is currently handled as an
abnormal situation and module's data section is not being unloaded. To
handle this situation without keeping module's data in memory, allow
codetags with longer lifespan than the module to be loaded into their own
separate memory. The in-use memory areas and gaps after module unloading
in this separate memory are tracked using maple trees. Allocation tags
arrange their separate memory so that it is virtually contiguous and that
will allow simple allocation tag indexing later on in this patchset. The
size of this virtually contiguous memory is set to store up to 100000
allocation tags.
[surenb@google.com: fix empty codetag module section handling]
Link: https://lkml.kernel.org/r/20241101000017.3856204-1-surenb@google.com
[akpm@linux-foundation.org: update comment, per Dan]
Link: https://lkml.kernel.org/r/20241023170759.999909-4-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Minchan Kim <minchan@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Huth <thuth@redhat.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xiongwei Song <xiongwei.song@windriver.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In order to support ROX allocations for module text, it is necessary to
handle modifications to the code, such as relocations and alternatives
patching, without write access to that memory.
One option is to use text patching, but this would make module loading
extremely slow and will expose executable code that is not finally formed.
A better way is to have memory allocated with ROX permissions contain
invalid instructions and keep a writable, but not executable copy of the
module text. The relocations and alternative patches would be done on the
writable copy using the addresses of the ROX memory. Once the module is
completely ready, the updated text will be copied to ROX memory using text
patching in one go and the writable copy will be freed.
Add support for that to module initialization code and provide necessary
interfaces in execmem.
Link: https://lkml.kernel.org/r/20241023162711.2579610-5-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewd-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: kdevops <kdevops@lists.linux.dev>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Song Liu <song@kernel.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Prior to commit d646969055 ("Reimplement RLIMIT_SIGPENDING on top of
ucounts") UCOUNT_RLIMIT_SIGPENDING rlimit was not enforced for a class of
signals. However now it's enforced unconditionally, even if
override_rlimit is set. This behavior change caused production issues.
For example, if the limit is reached and a process receives a SIGSEGV
signal, sigqueue_alloc fails to allocate the necessary resources for the
signal delivery, preventing the signal from being delivered with siginfo.
This prevents the process from correctly identifying the fault address and
handling the error. From the user-space perspective, applications are
unaware that the limit has been reached and that the siginfo is
effectively 'corrupted'. This can lead to unpredictable behavior and
crashes, as we observed with java applications.
Fix this by passing override_rlimit into inc_rlimit_get_ucounts() and skip
the comparison to max there if override_rlimit is set. This effectively
restores the old behavior.
Link: https://lkml.kernel.org/r/20241104195419.3962584-1-roman.gushchin@linux.dev
Fixes: d646969055 ("Reimplement RLIMIT_SIGPENDING on top of ucounts")
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Co-developed-by: Andrei Vagin <avagin@google.com>
Signed-off-by: Andrei Vagin <avagin@google.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Alexey Gladkov <legion@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The inc_rlimit_get_ucounts() increments the specified rlimit counter and
then checks its limit. If the value exceeds the limit, the function
returns an error without decrementing the counter.
Link: https://lkml.kernel.org/r/20241101191940.3211128-1-roman.gushchin@linux.dev
Fixes: 15bc01effe ("ucounts: Fix signal ucount refcounting")
Signed-off-by: Andrei Vagin <avagin@google.com>
Co-developed-by: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Tested-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Alexey Gladkov <legion@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Andrei Vagin <avagin@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
While PREEMPT_RT is undoubtedly totally awesome, it does not, at this
time, make sense to have all{yes,mod}config select it.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 35772d627b ("sched: Enable PREEMPT_DYNAMIC for PREEMPT_RT")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
For clarity. It's increasingly hard to reason about the code, when KASLR
is moving around the boundaries. In this case where KASLR is randomizing
the location of the kernel image within physical memory, the maximum
number of address bits for physical memory has not changed.
What has changed is the ending address of memory that is allowed to be
directly mapped by the kernel.
Let's name the variable, and the associated macro accordingly.
Also, enhance the comment above the direct_map_physmem_end definition,
to further clarify how this all works.
Link: https://lkml.kernel.org/r/20241009025024.89813-1-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jordan Niethe <jniethe@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
hrtimer_setup() and hrtimer_setup_on_stack() take the callback function
pointer as argument and initialize the timer completely.
Replace the hrtimer_init*() variants and the open coded initialization of
hrtimer::function with the new setup mechanism.
Switch to use the new functions.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/2bae912336103405adcdab96b88d3ea0353b4228.1730386209.git.namcao@linutronix.de
hrtimer_setup_on_stack() takes the callback function pointer as argument
and initializes the timer completely.
Replace hrtimer_init_on_stack() and the open coded initialization of
hrtimer::function with the new setup mechanism.
The conversion was done with Coccinelle.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/17f9421fed6061df4ad26a4cc91873d2c078cb0f.1730386209.git.namcao@linutronix.de
The hrtimer_init*() API is replaced by hrtimer_setup*() variants to
initialize the timer including the callback function at once.
hrtimer_init_sleeper_on_stack() does not need user to setup the callback
function separately, so a new variant would not be strictly necessary.
Nonetheless, to keep the naming convention consistent, introduce
hrtimer_setup_sleeper_on_stack(). hrtimer_init_on_stack() will be removed
once all users are converted.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/7b5e18e6dd0ace9eaa211201528cb9dc23752454.1730386209.git.namcao@linutronix.de
To initialize hrtimer on stack, hrtimer_init_on_stack() needs to be called
and also hrtimer::function must be set. This is error-prone and awkward to
use.
Introduce hrtimer_setup_on_stack() which does both of these things, so that
users of hrtimer can be simplified.
The new setup function also has a sanity check for the provided function
pointer. If NULL, a warning is emitted and a dummy callback installed.
hrtimer_init_on_stack() will be removed as soon as all of its users have
been converted to the new function.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/4b05e2ab3a82c517adf67fabc0f0cd8fe118b97c.1730386209.git.namcao@linutronix.de
To initialize hrtimer, hrtimer_init() needs to be called and also
hrtimer::function must be set. This is error-prone and awkward to use.
Introduce hrtimer_setup() which does both of these things, so that users of
hrtimer can be simplified.
The new setup function also has a sanity check for the provided function
pointer. If NULL, a warning is emitted and a dummy callback installed.
hrtimer_init() will be removed as soon as all of its users have been
converted to the new function.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/5057c1ddbfd4b92033cd93d37fe38e6b069d5ba6.1730386209.git.namcao@linutronix.de
hrtimer_init*_on_stack() is not covered by tracing when
CONFIG_DEBUG_OBJECTS_TIMERS=y.
Rework the functions similar to hrtimer_init() and hrtimer_init_sleeper()
so that the hrtimer_init() tracepoint is unconditionally available.
The rework makes hrtimer_init_sleeper() unused. Delete it.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/74528e8abf2bb96e8bee85ffacbf14e15cf89f0d.1730386209.git.namcao@linutronix.de
The timer and hrtimer soft interrupts are raised in hard interrupt
context. With threaded interrupts force enabled or on PREEMPT_RT this leads
to waking the ksoftirqd for the processing of the soft interrupt.
ksoftirqd runs as SCHED_OTHER task which means it will compete with other
tasks for CPU resources. This can introduce long delays for timer
processing on heavy loaded systems and is not desired.
Split the TIMER_SOFTIRQ and HRTIMER_SOFTIRQ processing into a dedicated
timers thread and let it run at the lowest SCHED_FIFO priority.
Wake-ups for RT tasks happen from hardirq context so only timer_list timers
and hrtimers for "regular" tasks are processed here. The higher priority
ensures that wakeups are performed before scheduling SCHED_OTHER tasks.
Using a dedicated variable to store the pending softirq bits values ensure
that the timer are not accidentally picked up by ksoftirqd and other
threaded interrupts.
It shouldn't be picked up by ksoftirqd since it runs at lower priority.
However if ksoftirqd is already running while a timer fires, then ksoftird
will be PI-boosted due to the BH-lock to ktimer's priority.
The timer thread can pick up pending softirqs from ksoftirqd but only
if the softirq load is high. It is not be desired that the picked up
softirqs are processed at SCHED_FIFO priority under high softirq load
but this can already happen by a PI-boost by a force-threaded interrupt.
[ frederic@kernel.org: rcutorture.c fixes, storm fix by introduction of
local_timers_pending() for tick_nohz_next_event() ]
[ junxiao.chang@intel.com: Ensure ktimersd gets woken up even if a
softirq is currently served. ]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org> [rcutorture]
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241106150419.2593080-4-bigeasy@linutronix.de
Raising the timer soft interrupt is always done from hard interrupt
context, so it can be reduced to just setting the TIMER soft interrupt
flag. The soft interrupt will be invoked on return from interrupt.
Use therefore __raise_softirq_irqoff() to raise the TIMER soft interrupt,
which is a trivial optimization.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241106150419.2593080-3-bigeasy@linutronix.de
Raising the hrtimer soft interrupt is always done from hard interrupt
context, so it can be reduced to just setting the HRTIMER soft interrupt
flag. The soft interrupt will be invoked on return from interrupt.
Use therefore __raise_softirq_irqoff() to raise the HRTIMER soft interrupt,
which is a trivial optimization.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241106150419.2593080-2-bigeasy@linutronix.de
Now that the SIG_IGN problem is solved in the core code, the alarmtimer
callbacks do not require a return value anymore.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241105064214.318837272@linutronix.de
Now that ignored posix timer signals are requeued and the timers are
rearmed on signal delivery the workaround to keep such timers alive and
self rearm them is not longer required.
Remove the unused alarm timer parts.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064214.252443020@linutronix.de
Now that ignored posix timer signals are requeued and the timers are
rearmed on signal delivery the workaround to keep such timers alive and
self rearm them is not longer required.
Remove the relevant hacks and the not longer required return values from
the related functions. The alarm timer workarounds will be cleaned up in a
separate step.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064214.187239060@linutronix.de
Queue posixtimers which have their signal ignored on the ignored list:
1) When the timer fires and the signal has SIG_IGN set
2) When SIG_IGN is installed via sigaction() and a timer signal
is already queued
This only happens when the signal is for a valid timer, which delivered the
signal in periodic mode. One-shot timer signals are correctly dropped.
Due to the lock order constraints (sighand::siglock nests inside
timer::lock) the signal code cannot access any of the timer fields which
are relevant to make this decision, e.g. timer::it_status.
This is addressed by establishing a protection scheme which requires to
lock both locks on the timer side for modifying decision fields in the
timer struct and therefore makes it possible for the signal delivery to
evaluate with only sighand:siglock being held:
1) Move the NULLification of timer->it_signal into the sighand::siglock
protected section of timer_delete() and check timer::it_signal in the
code path which determines whether the signal is dropped or queued on
the ignore list.
This ensures that a deleted timer cannot be moved onto the ignore
list, which would prevent it from being freed on exit() as it is not
longer in the process' posix timer list.
If the timer got moved to the ignored list before deletion then it is
removed from the ignored list under sighand lock in timer_delete().
2) Provide a new timer::it_sig_periodic flag, which gets set in the
signal queue path with both timer and sighand locks held if the timer
is actually in periodic mode at expiry time.
The ignore list code checks this flag under sighand::siglock and drops
the signal when it is not set.
If it is set, then the signal is moved to the ignored list independent
of the actual state of the timer.
When the signal is un-ignored later then the signal is moved back to
the signal queue. On signal delivery the posix timer side decides
about dropping the signal if the timer was re-armed, dis-armed or
deleted based on the signal sequence counter check.
If the thread/process exits then not yet delivered signals are
discarded which means the reference of the timer containing the
sigqueue is dropped and frees the timer.
This is way cheaper than requiring all code paths to lock
sighand::siglock of the target thread/process on any modification of
timer::it_status or going all the way and removing pending signals
from the signal queues on every rearm, disarm or delete operation.
So the protection scheme here is that on the timer side both timer::lock
and sighand::siglock have to be held for modifying
timer::it_signal
timer::it_sig_periodic
which means that on the signal side holding sighand::siglock is enough to
evaluate these fields.
In posixtimer_deliver_signal() holding timer::lock is sufficient to do the
sequence validation against timer::it_signal_seq because a concurrent
expiry is waiting on timer::lock to be released.
This completes the SIG_IGN handling and such timers are not longer self
rearmed which avoids pointless wakeups.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064214.120756416@linutronix.de
When a real handler (including SIG_DFL) is installed for a signal, which
had previously SIG_IGN set, then the list of ignored posix timers has to be
checked for timers which are affected by this change.
Add a list walk function which checks for the matching signal number and if
found requeues the timers signal, so the timer is rearmed on signal
delivery.
Rearming the timer right away is not possible because that requires to drop
sighand lock.
No functional change as the counter part which queues the timers on the
ignored list is still missing.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064214.054091076@linutronix.de
To handle posix timer signals on sigaction(SIG_IGN) properly, the timers
will be queued on a separate ignored list.
Add the necessary cleanup code for timer_delete() and exit_itimers().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.987530588@linutronix.de
To prepare for handling posix timer signals on sigaction(SIG_IGN) properly,
add a list to task::signal.
This list will be used to queue posix timers so their signal can be
requeued when SIG_IGN is lifted later.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.920101900@linutronix.de
The posix timer signal handling uses siginfo::si_sys_private for handling
the sequence counter check. That indirection is not longer required and the
sequence count value at signal queueing time can be stored in struct
k_itimer itself.
This removes the requirement of treating siginfo::si_sys_private special as
it's now always zero as the kernel does not touch it anymore.
Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lore.kernel.org/all/20241105064213.852619866@linutronix.de
Remove the leftovers of sigqueue preallocation as it's not longer used.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.786506636@linutronix.de
To cure the SIG_IGN handling for posix interval timers, the preallocated
sigqueue needs to be embedded into struct k_itimer to prevent life time
races of all sorts.
Now that the prerequisites are in place, embed the sigqueue into struct
k_itimer and fixup the relevant usage sites.
Aside of preparing for proper SIG_IGN handling, this spares an extra
allocation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.719695194@linutronix.de
In preparation for handling ignored posix timer signals correctly and
embedding the sigqueue struct into struct k_itimer, hand down a pointer to
the sigqueue struct into posix_timer_deliver_signal() instead of just
having a boolean flag.
No functional change.
Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lore.kernel.org/all/20241105064213.652658158@linutronix.de
To handle posix timers which have their signal ignored via SIG_IGN properly
it is required to requeue a ignored signal for delivery when SIG_IGN is
lifted so the timer gets rearmed.
Split the required code out of send_sigqueue() so it can be reused in
context of sigaction().
While at it rename send_sigqueue() to posixtimer_send_sigqueue() so its
clear what this is about.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.586453412@linutronix.de
instead of re-evaluating the signal delivery mode everywhere.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.519086500@linutronix.de
To cure the SIG_IGN handling for posix interval timers, the preallocated
sigqueue needs to be embedded into struct k_itimer to prevent life time
races of all sorts.
Provide a new function to initialize the embedded sigqueue to prepare for
that.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.450427515@linutronix.de
To cure the SIG_IGN handling for posix interval timers, the preallocated
sigqueue needs to be embedded into struct k_itimer to prevent life time
races of all sorts.
Reorganize __sigqueue_alloc() so the ucounts retrieval and the
initialization can be used independently.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.371410037@linutronix.de
To cure the SIG_IGN handling for posix interval timers, the preallocated
sigqueue needs to be embedded into struct k_itimer to prevent life time
races of all sorts.
To make that work correctly it needs reference counting so that timer
deletion does not free the timer prematuraly when there is a signal queued
or delivered concurrently.
Add a rcuref to the posix timer part.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.304756440@linutronix.de
POSIX CPU timer nanosleep creates a k_itimer on stack and uses the sigq
pointer to detect the nanosleep case in the expiry function.
Prepare for embedding sigqueue into struct k_itimer by using a dedicated
flag for nanosleep.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.238550394@linutronix.de
The firing flag of a posix CPU timer is tristate:
0: when the timer is not about to deliver a signal
1: when the timer has expired, but the signal has not been delivered yet
-1: when the timer was queued for signal delivery and a rearm operation
raced against it and supressed the signal delivery.
This is a pointless exercise as this can be simply expressed with a
boolean. Only if set, the signal is delivered. This makes delete and rearm
consistent with the rest of the posix timers.
Convert firing to bool and fixup the usage sites accordingly and add
comments why the timer cannot be dequeued right away.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241105064213.172848618@linutronix.de
The handling of the timer overrun in the signal code is inconsistent as it
takes previous overruns into account. This is just wrong as after the
reprogramming of a timer the overrun count starts over from a clean state,
i.e. 0.
Don't touch info::si_overrun in send_sigqueue() and only store the overrun
value at signal delivery time, which is computed from the timer itself
relative to the expiry time.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.106738193@linutronix.de
Signals of timers which are reprogammed, disarmed or deleted can deliver
signals related to the past. The POSIX spec is blury about this:
- "The effect of disarming or resetting a timer with pending expiration
notifications is unspecified."
- "The disposition of pending signals for the deleted timer is
unspecified."
In both cases it is reasonable to expect that pending signals are
discarded. Especially in the reprogramming case it does not make sense to
account for previous overruns or to deliver a signal for a timer which has
been disarmed. This makes the behaviour consistent and understandable.
Remove the si_sys_private check from the signal delivery code and invoke
posix_timer_deliver_signal() unconditionally for posix timer related
signals.
Change posix_timer_deliver_signal() so it controls the actual signal
delivery via the return value. It now instructs the signal code to drop the
signal when:
1) The timer does not longer exist in the hash table
2) The timer signal_seq value is not the same as the si_sys_private value
which was set when the signal was queued.
This is also a preparatory change to embed the sigqueue into the k_itimer
structure, which in turn allows to remove the si_sys_private magic.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241105064213.040348644@linutronix.de
If posix_cpu_timer_del() exits early due to task not found or sighand
invalid, it fails to clear the state of the timer. That's harmless but
inconsistent.
These early exits are accounted as successful delete. Move the update of
the timer state into the success return path, so all "successful" deletions
are handled.
Reported-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241105064212.974053438@linutronix.de
Currently, if __region_intersects() finds any overlapped but unmatched
resource, it walks the descendant resource tree to check for overlapped
and matched descendant resources using for_each_resource(). However, in
current kernel, for_each_resource() iterates not only the descendant tree,
but also subsequent sibling trees in certain scenarios. While this
doesn't introduce bugs, it makes code hard to be understood and
potentially inefficient.
So, the patch revises next_resource() and for_each_resource() and makes
for_each_resource() traverse the subtree under the specified subtree root
only. Test shows that this avoids unnecessary resource tree walking in
__region_intersects().
For the example resource tree as follows,
X
|
A----D----E
|
B--C
if 'A' is the overlapped but unmatched resource, original kernel
iterates 'B', 'C', 'D', 'E' when it walks the descendant tree. While
the patched kernel iterates only 'B', 'C'.
Thanks David Hildenbrand for providing a good resource tree example.
Link: https://lkml.kernel.org/r/20241029122735.79164-1-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The commit 78ff640819 ("vfs: Convert tracefs to use the new mount API")
broke the gid setting when set by fstab or other mount utility.
It is ignored when it is set. Fix the code so that it recognises the
option again and will honor the settings on mount at boot up.
Update the internal documentation and create a selftest to make sure
it doesn't break again in the future.
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Merge tag 'tracefs-v6.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracefs fixes from Steven Rostedt:
"Fix tracefs mount options.
Commit 78ff640819 ("vfs: Convert tracefs to use the new mount API")
broke the gid setting when set by fstab or other mount utility. It is
ignored when it is set. Fix the code so that it recognises the option
again and will honor the settings on mount at boot up.
Update the internal documentation and create a selftest to make sure
it doesn't break again in the future"
* tag 'tracefs-v6.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/selftests: Add tracefs mount options test
tracing: Document tracefs gid mount option
tracing: Fix tracefs mount options
After introducing the default builtin swap implementation, update the
min_heap_callbacks to replace the swp function pointer with NULL. This
change allows the min heap to directly utilize the builtin swap,
simplifying the code.
Link: https://lkml.kernel.org/r/20241020040200.939973-6-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Coly Li <colyli@suse.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Sakai <msakai@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Enhance min heap API with non-inline functions and
optimizations", v2.
Add non-inline versions of the min heap API functions in lib/min_heap.c
and updates all users outside of kernel/events/core.c to use these
non-inline versions. To mitigate the performance impact of indirect
function calls caused by the non-inline versions of the swap and compare
functions, a builtin swap has been introduced that swaps elements based on
their size. Additionally, it micro-optimizes the efficiency of the min
heap by pre-scaling the counter, following the same approach as in
lib/sort.c. Documentation for the min heap API has also been added to the
core-api section.
This patch (of 10):
All current min heap API functions are marked with '__always_inline'.
However, as the number of users increases, inlining these functions
everywhere leads to a increase in kernel size.
In performance-critical paths, such as when perf events are enabled and
min heap functions are called on every context switch, it is important to
retain the inline versions for optimal performance. To balance this, the
original inline functions are kept, and additional non-inline versions of
the functions have been added in lib/min_heap.c.
Link: https://lkml.kernel.org/r/20241020040200.939973-1-visitorckw@gmail.com
Link: https://lore.kernel.org/20240522161048.8d8bbc7b153b4ecd92c50666@linux-foundation.org
Link: https://lkml.kernel.org/r/20241020040200.939973-2-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Coly Li <colyli@suse.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Sakai <msakai@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use ERR_PTR_PCPU() when returning error pointer in the percpu address
space. Use IS_ERR_PCPU() and PTR_ERR_PCPU() when returning the error
pointer from the percpu address space. These macros add intermediate cast
to unsigned long when switching named address spaces.
The patch will avoid future build errors due to pointer address space
mismatch with enabled strict percpu address space checks.
Link: https://lkml.kernel.org/r/20240924090813.1353586-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
All the functions related to the reboot notifier list are in
kernel/reboot.c. Move the list itself, too. As there are no direct users
anymore, make the declaration static.
Link: https://lkml.kernel.org/r/20241012-reboot_notifier_list-v1-1-6093bb9455ce@weissschuh.net
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
reallocate_resource() documentation claims constraint is about "the size
and alignment" but the size is provided in another parameter. Instead of
size, constraint has the allowed memory range (min, max) so change the
wording to reflect that.
Link: https://lkml.kernel.org/r/20241009125751.8090-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Using strscpy() to read the task comm ensures that the name is always
NUL-terminated, regardless of the source string. This approach also
facilitates future extensions to the task comm.
Link: https://lkml.kernel.org/r/20241007144911.27693-3-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Justin Stitt <justinstitt@google.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Alejandro Colomar <alx@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matus Jokay <matus.jokay@stuba.sk>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Quentin Monnet <qmo@kernel.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Improve the copy of task comm", v8.
Using {memcpy,strncpy,strcpy,kstrdup} to copy the task comm relies on the
length of task comm. Changes in the task comm could result in a
destination string that is overflow. Therefore, we should explicitly
ensure the destination string is always NUL-terminated, regardless of the
task comm. This approach will facilitate future extensions to the task
comm.
As suggested by Linus [0], we can identify all relevant code with the
following git grep command:
git grep 'memcpy.*->comm\>'
git grep 'kstrdup.*->comm\>'
git grep 'strncpy.*->comm\>'
git grep 'strcpy.*->comm\>'
PATCH #2~#4: memcpy
PATCH #5~#6: kstrdup
PATCH #7: strcpy
Please note that strncpy() is not included in this series as it is being
tracked by another effort. [1]
This patch (of 7):
We want to eliminate the use of __get_task_comm() for the following
reasons:
- The task_lock() is unnecessary
Quoted from Linus [0]:
: Since user space can randomly change their names anyway, using locking
: was always wrong for readers (for writers it probably does make sense
: to have some lock - although practically speaking nobody cares there
: either, but at least for a writer some kind of race could have
: long-term mixed results
Link: https://lkml.kernel.org/r/20241007144911.27693-1-laoar.shao@gmail.com
Link: https://lkml.kernel.org/r/20241007144911.27693-2-laoar.shao@gmail.com
Link: https://lore.kernel.org/all/CAHk-=wivfrF0_zvf+oj6==Sh=-npJooP8chLPEfaFV0oNYTTBA@mail.gmail.com [0]
Link: https://lore.kernel.org/all/CAHk-=whWtUC-AjmGJveAETKOMeMFSTwKwu99v7+b6AyHMmaDFA@mail.gmail.com/
Link: https://lore.kernel.org/all/CAHk-=wjAmmHUg6vho1KjzQi2=psR30+CogFd4aXrThr2gsiS4g@mail.gmail.com/ [0]
Link: https://github.com/KSPP/linux/issues/90 [1]
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Matus Jokay <matus.jokay@stuba.sk>
Cc: Alejandro Colomar <alx@kernel.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Quentin Monnet <qmo@kernel.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There are already a couple of places where we may replace a few lines of
code by calling a helper, which increases readability while deduplicating
the code.
Introduce is_type_match() helper and use it.
Link: https://lkml.kernel.org/r/20240925154355.1170859-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "resource: A couple of cleanups".
A couple of ad-hoc cleanups since there was a recent development of
the code in question. No functional changes intended.
This patch (of 2):
__region_intersects() uses open coded resource_intersection(). Replace it
with existing API which also make more clear what we are checking.
Link: https://lkml.kernel.org/r/20240925154355.1170859-1-andriy.shevchenko@linux.intel.com
Link: https://lkml.kernel.org/r/20240925154355.1170859-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The following errors are observed when kexec is done with SMT=off on
powerpc.
[ 358.458385] Removing IBM Power 842 compression device
[ 374.795734] kexec_core: Starting new kernel
[ 374.795748] kexec: Waking offline cpu 1.
[ 374.875695] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
[ 374.935833] kexec: Waking offline cpu 2.
[ 375.015664] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
snip..
[ 375.515823] kexec: Waking offline cpu 6.
[ 375.635667] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
[ 375.695836] kexec: Waking offline cpu 7.
To avoid kexec kernel boot failure on PowerPC, all the present CPUs that
are offline are brought online during kexec. For more information, refer
to commit e8e5c2155b ("powerpc/kexec: Fix orphaned offline CPUs across
kexec"). Bringing the CPUs online triggers the crash hotplug handler,
crash_handle_hotplug_event(), to update the kdump image. Since the system
is on the kexec kernel boot path and the kexec lock is held, the
crash_handle_hotplug_event() function fails to acquire the same lock to
update the kdump image, resulting in the error messages mentioned above.
To fix this, return from crash_handle_hotplug_event() without printing the
error message if kexec is in progress.
The same applies to the crash_check_hotplug_support() function. Return 0
if kexec is in progress because kernel is not in a position to update the
kdump image.
Link: https://lkml.kernel.org/r/20240921103745.560430-1-sourabhjain@linux.ibm.com
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Acked-by: Baoquan he <bhe@redhat.com>
Reported-by: Sachin P Bappalige <sachinpb@linux.vnet.ibm.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The types of mm flags are now far beyond the core dump related features.
This patch moves mm flags from linux/sched/coredump.h to linux/mm_types.h.
The linux/sched/coredump.h has include the mm_types.h, so the C files
related to coredump does not need to change head file inclusion. In
addition, the inclusion of sched/coredump.h now can be deleted from the C
files that irrelevant to core dump.
Link: https://lkml.kernel.org/r/20240926074922.2721274-1-sunnanyong@huawei.com
Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm_access() can return NULL if the mm is not found, but this is handled
the same as an error in all callers, with some translating this into an
-ESRCH error.
Only proc_mem_open() returns NULL if no mm is found, however in this case
it is clearer and makes more sense to explicitly handle the error.
Additionally we take the opportunity to refactor the function to eliminate
unnecessary nesting.
Simplify things by simply returning -ESRCH if no mm is found - this both
eliminates confusing use of the IS_ERR_OR_NULL() macro, and simplifies
callers which would return -ESRCH by returning this error directly.
[lorenzo.stoakes@oracle.com: prefer neater pointer error comparison]
Link: https://lkml.kernel.org/r/2fae1834-749a-45e1-8594-5e5979cf7103@lucifer.local
Link: https://lkml.kernel.org/r/20240924201023.193135-1-lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hardware traces, such as instruction traces, can produce a vast amount of
trace data, so being able to reduce tracing to more specific circumstances
can be useful.
The ability to pause or resume tracing when another event happens, can do
that.
Add ability for an event to "pause" or "resume" AUX area tracing.
Add aux_pause bit to perf_event_attr to indicate that, if the event
happens, the associated AUX area tracing should be paused. Ditto
aux_resume. Do not allow aux_pause and aux_resume to be set together.
Add aux_start_paused bit to perf_event_attr to indicate to an AUX area
event that it should start in a "paused" state.
Add aux_paused to struct hw_perf_event for AUX area events to keep track of
the "paused" state. aux_paused is initialized to aux_start_paused.
Add PERF_EF_PAUSE and PERF_EF_RESUME modes for ->stop() and ->start()
callbacks. Call as needed, during __perf_event_output(). Add
aux_in_pause_resume to struct perf_buffer to prevent races with the NMI
handler. Pause/resume in NMI context will miss out if it coincides with
another pause/resume.
To use aux_pause or aux_resume, an event must be in a group with the AUX
area event as the group leader.
Example (requires Intel PT and tools patches also):
$ perf record --kcore -e intel_pt/aux-action=start-paused/k,syscalls:sys_enter_newuname/aux-action=resume/,syscalls:sys_exit_newuname/aux-action=pause/ uname
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.043 MB perf.data ]
$ perf script --call-trace
uname 30805 [000] 24001.058782799: name: 0x7ffc9c1865b0
uname 30805 [000] 24001.058784424: psb offs: 0
uname 30805 [000] 24001.058784424: cbr: 39 freq: 3904 MHz (139%)
uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) debug_smp_processor_id
uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) __x64_sys_newuname
uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) down_read
uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) __cond_resched
uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_add
uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) in_lock_functions
uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_sub
uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) up_read
uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_add
uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) in_lock_functions
uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) preempt_count_sub
uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) _copy_to_user
uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) syscall_exit_to_user_mode
uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) syscall_exit_work
uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) perf_syscall_exit
uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) debug_smp_processor_id
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_trace_buf_alloc
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_swevent_get_recursion_context
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) debug_smp_processor_id
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) debug_smp_processor_id
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_tp_event
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_trace_buf_update
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) tracing_gen_ctx_irq_test
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_swevent_event
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __perf_event_account_interrupt
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __this_cpu_preempt_check
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_event_output_forward
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_event_aux_pause
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) ring_buffer_get
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __rcu_read_lock
uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __rcu_read_unlock
uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) pt_event_stop
uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) debug_smp_processor_id
uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) debug_smp_processor_id
uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) native_write_msr
uname 30805 [000] 24001.058785463: ([kernel.kallsyms]) native_write_msr
uname 30805 [000] 24001.058785639: 0x0
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: James Clark <james.clark@arm.com>
Link: https://lkml.kernel.org/r/20241022155920.17511-3-adrian.hunter@intel.com
In order to enable PREEMPT_DYNAMIC for PREEMPT_RT, remove PREEMPT_RT
from the 'Preemption Model' choice. Strictly speaking PREEMPT_RT is
not a change in how preemption works, but rather it makes a ton more
code preemptible.
Notably, take away NONE and VOLUNTARY options for PREEMPT_RT, they make
no sense (but are techincally possible).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20241007075055.441622332@infradead.org
Change fair to use resched_curr_lazy(), which, when the lazy
preemption model is selected, will set TIF_NEED_RESCHED_LAZY.
This LAZY bit will be promoted to the full NEED_RESCHED bit on tick.
As such, the average delay between setting LAZY and actually
rescheduling will be TICK_NSEC/2.
In short, Lazy preemption will delay preemption for fair class but
will function as Full preemption for all the other classes, most
notably the realtime (RR/FIFO/DEADLINE) classes.
The goal is to bridge the performance gap with Voluntary, such that we
might eventually remove that option entirely.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20241007075055.331243614@infradead.org
Add the basic infrastructure to split the TIF_NEED_RESCHED bit in two.
Either bit will cause a resched on return-to-user, but only
TIF_NEED_RESCHED will drive IRQ preemption.
No behavioural change intended.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20241007075055.219540785@infradead.org
Instead of solving the underlying problem of the double invocation of
__sched_fork() for idle tasks, sched-ext decided to hack around the issue
by partially clearing out the entity struct to preserve the already
enqueued node. A provided analysis and solution has been ignored for four
months.
Now that someone else has taken care of cleaning it up, remove the
disgusting hack and clear out the full structure. Remove the comment in the
structure declaration as well, as there is no requirement for @node being
the last element anymore.
Fixes: f0e1a0643a ("sched_ext: Implement BPF extensible scheduler class")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/87ldy82wkc.ffs@tglx
Idle tasks are initialized via __sched_fork() twice:
fork_idle()
copy_process()
sched_fork()
__sched_fork()
init_idle()
__sched_fork()
Instead of cleaning this up, sched_ext hacked around it. Even when analyis
and solution were provided in a discussion, nobody cared to clean this up.
init_idle() is also invoked from sched_init() to initialize the boot CPU's
idle task, which requires the __sched_fork() invocation. But this can be
trivially solved by invoking __sched_fork() before init_idle() in
sched_init() and removing the __sched_fork() invocation from init_idle().
Do so and clean up the comments explaining this historical leftover.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241028103142.359584747@linutronix.de
Switch all instrumentable users of the seqcount_latch interface over to
the non-raw interface.
Co-developed-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241104161910.780003-5-elver@google.com
Most of sched_clock()'s implementation is ineligible for instrumentation
due to relying on sched_clock_noinstr().
Split the implementation off into an __always_inline function
__sched_clock(), which is then used by the noinstr and instrumentable
version, to allow more of sched_clock() to be covered by various
instrumentation.
This will allow instrumentation with the various sanitizers (KASAN,
KCSAN, KMSAN, UBSAN). For KCSAN, we know that raw seqcount_latch usage
without annotations will result in false positive reports: tell it that
all of __sched_clock() is "atomic" for the latch reader; later changes
in this series will take care of the writers.
Co-developed-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241104161910.780003-3-elver@google.com
Swap the writes to the odd and even copies to make the writer critical
section look like all other seqcount_latch writers.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241104161910.780003-2-elver@google.com
On some devices there are HW dependencies for shared frequency and voltage
between devices. It will impact Energy Aware Scheduler (EAS) decision,
where CPUs share the voltage & frequency domain with other CPUs or devices
e.g.
- Mid CPUs + Big CPU
- Little CPU + L3 cache in DSU
- some other device + Little CPUs
Detailed explanation of one example:
When the L3 cache frequency is increased, the affected Little CPUs might
run at higher voltage and frequency. That higher voltage causes higher CPU
power and thus more energy is used for running the tasks. This is
important for background running tasks, which try to run on energy
efficient CPUs.
Therefore, add performance state limits which are applied for the device
(in this case CPU). This is important on SoCs with HW dependencies
mentioned above so that the Energy Aware Scheduler (EAS) does not use
performance states outside the valid min-max range for energy calculation.
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://patch.msgid.link/20241030164126.1263793-2-lukasz.luba@arm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
