The canonical location for the tracefs filesystem is at /sys/kernel/tracing.
But, from Documentation/trace/ftrace.rst:
Before 4.1, all ftrace tracing control files were within the debugfs
file system, which is typically located at /sys/kernel/debug/tracing.
For backward compatibility, when mounting the debugfs file system,
the tracefs file system will be automatically mounted at:
/sys/kernel/debug/tracing
Many comments and samples in the bpf code still refer to this older
debugfs path, so let's update them to avoid confusion. There are a few
spots where the bpf code explicitly checks both tracefs and debugfs
(tools/bpf/bpftool/tracelog.c and tools/lib/api/fs/fs.c) and I've left
those alone so that the tools can continue to work with both paths.
Signed-off-by: Ross Zwisler <zwisler@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20230313205628.1058720-2-zwisler@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We have switched to memcg-based memory accouting and thus the rlimit is
not needed any more. LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK was introduced in
libbpf for backward compatibility, so we can use it instead now.
This patch also removes the useless header sys/resource.h from many files
in samples/bpf.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220409125958.92629-2-laoar.shao@gmail.com
While cross compiling on ARM32 , the casting from pointer to __u64 will
cause warnings:
samples/bpf/task_fd_query_user.c: In function 'main':
samples/bpf/task_fd_query_user.c:399:23: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
399 | uprobe_file_offset = (__u64)main - (__u64)&__executable_start;
| ^
samples/bpf/task_fd_query_user.c:399:37: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
399 | uprobe_file_offset = (__u64)main - (__u64)&__executable_start;
Workaround this by using "unsigned long" to adapt to different ARCHs.
Signed-off-by: Hailong Liu <liu.hailong6@zte.com.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210511140429.89426-1-liuhailongg6@163.com
Since bpf is not using rlimit memlock for the memory accounting
and control, do not change the limit in sample applications.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201201215900.3569844-35-guro@fb.com
This commit refactors the existing kprobe program with libbpf bpf
loader. To attach bpf program, this uses generic bpf_program__attach()
approach rather than using bpf_load's load_bpf_file().
To attach bpf to perf_event, instead of using previous ioctl method,
this commit uses bpf_program__attach_perf_event since it manages the
enable of perf_event and attach of BPF programs to it, which is much
more intuitive way to achieve.
Also, explicit close(fd) has been removed since event will be closed
inside bpf_link__destroy() automatically.
Furthermore, to prevent conflict of same named uprobe events, O_TRUNC
flag has been used to clear 'uprobe_events' interface.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201124090310.24374-4-danieltimlee@gmail.com
The memlock rlimit is a notorious source of failure for BPF programs. Most
of the samples just set it to infinity, but a few used a lower limit. The
problem with unconditionally setting a lower limit is that this will also
override the limit if the system-wide setting is *higher* than the limit
being set, which can lead to failures on systems that lock a lot of memory,
but set 'ulimit -l' to unlimited before running a sample.
One fix for this is to only conditionally set the limit if the current
limit is lower, but it is simpler to just unify all the samples and have
them all set the limit to infinity.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/20201026233623.91728-1-toke@redhat.com
>From commit f1394b7988 ("block: mark blk_account_io_completion
static") symbol blk_account_io_completion() has been marked as static,
which makes it no longer possible to attach kprobe to this event.
Currently, there are broken samples due to this reason.
As a solution to this, attach kprobe events to blk_account_io_done()
to modify them to perform the same behavior as before.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200818051641.21724-1-danieltimlee@gmail.com
Fix all files in samples/bpf to include libbpf header files with the bpf/
prefix, to be consistent with external users of the library. Also ensure
that all includes of exported libbpf header files (those that are exported
on 'make install' of the library) use bracketed includes instead of quoted.
To make sure no new files are introduced that doesn't include the bpf/
prefix in its include, remove tools/lib/bpf from the include path entirely,
and use tools/lib instead.
Fixes: 6910d7d386 ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157952560911.1683545.8795966751309534150.stgit@toke.dk
Add missing include for <linux/perf_event.h> which was removed from
perf-sys.h in commit 91854f9a07 ("perf tools: Move everything
related to sys_perf_event_open() to perf-sys.h").
Fixes: 91854f9a07 ("perf tools: Move everything related to sys_perf_event_open() to perf-sys.h")
Reported-by: KP Singh <kpsingh@google.com>
Reported-by: Florent Revest <revest@google.com>
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: KP Singh <kpsingh@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20191001112249.27341-1-bjorn.topel@gmail.com
GCC 9 fails to calculate the size of local constant strings and produces a
false positive:
samples/bpf/task_fd_query_user.c: In function ‘test_debug_fs_uprobe’:
samples/bpf/task_fd_query_user.c:242:67: warning: ‘%s’ directive output may be truncated writing up to 255 bytes into a region of size 215 [-Wformat-truncation=]
242 | snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%ss/%s/id",
| ^~
243 | event_type, event_alias);
| ~~~~~~~~~~~
samples/bpf/task_fd_query_user.c:242:2: note: ‘snprintf’ output between 45 and 300 bytes into a destination of size 256
242 | snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%ss/%s/id",
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
243 | event_type, event_alias);
| ~~~~~~~~~~~~~~~~~~~~~~~~
Workaround this by lowering the buffer size to a reasonable value.
Related GCC Bugzilla: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83431
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Currently, running sample "task_fd_query" and "tracex3" occurs the
following error. On kernel v5.0-rc* this sample will be unavailable
due to the removal of function 'blk_start_request' at commit "a1ce35f".
(function removed, as "Single Queue IO scheduler" no longer exists)
$ sudo ./task_fd_query
failed to create kprobe 'blk_start_request' error 'No such file or
directory'
This commit will change the function 'blk_start_request' to
'blk_mq_start_request' to fix the broken sample.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This is mostly to test kprobe/uprobe which needs kernel headers.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
