linux.git/Documentation/trace, branch v6.6.131 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git Documentation: tracing: Add PCI tracepoint documentation 2026-03-04T12:19:43+00:00 Shuai Xue xueshuai@linux.alibaba.com 2025-12-10T13:29:07+00:00 a4176432d41e1b81d9fddf638207df27608adbea [ Upstream commit 8236fc613d44e59f6736d6c3e9efffaf26ab7f00 ] The PCI tracing system provides tracepoints to monitor critical hardware events that can impact system performance and reliability. Add documentation about it. Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com> [bhelgaas: squash fixes: https://lore.kernel.org/r/20260108013956.14351-2-bagasdotme@gmail.com https://lore.kernel.org/r/20260108013956.14351-3-bagasdotme@gmail.com] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://patch.msgid.link/20251210132907.58799-4-xueshuai@linux.alibaba.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 8236fc613d44e59f6736d6c3e9efffaf26ab7f00 ]

The PCI tracing system provides tracepoints to monitor critical hardware
events that can impact system performance and reliability. Add
documentation about it.

Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
[bhelgaas: squash fixes:
https://lore.kernel.org/r/20260108013956.14351-2-bagasdotme@gmail.com
https://lore.kernel.org/r/20260108013956.14351-3-bagasdotme@gmail.com]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20251210132907.58799-4-xueshuai@linux.alibaba.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Documentation: trace: Refactor toctree 2026-03-04T12:19:43+00:00 Purva Yeshi purvayeshi550@gmail.com 2025-04-16T02:40:50+00:00 60b896647d888e7eb91c06b839f6e51f7dc22457 [ Upstream commit f0ba72e65516d1d86f40c79a49c4ba01c9555592 ] Refactor table of contents of kernel tracing subsystem docs to improve clarity, structure, and organization: - Reformat sections and add appropriate headings - Improve section grouping and refine descriptions for each group - Add docs intro paragraph Signed-off-by: Purva Yeshi <purvayeshi550@gmail.com> Link: https://lore.kernel.org/r/20250318113230.24950-2-purvayeshi550@gmail.com [Bagas: massage commit message and address reviews] Co-developed-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Stable-dep-of: 8236fc613d44 ("Documentation: tracing: Add PCI tracepoint documentation") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit f0ba72e65516d1d86f40c79a49c4ba01c9555592 ]

Refactor table of contents of kernel tracing subsystem docs to improve
clarity, structure, and organization:

- Reformat sections and add appropriate headings
- Improve section grouping and refine descriptions for each group
- Add docs intro paragraph

Signed-off-by: Purva Yeshi <purvayeshi550@gmail.com>
Link: https://lore.kernel.org/r/20250318113230.24950-2-purvayeshi550@gmail.com
[Bagas: massage commit message and address reviews]
Co-developed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Stable-dep-of: 8236fc613d44 ("Documentation: tracing: Add PCI tracepoint documentation")
Signed-off-by: Sasha Levin <sashal@kernel.org>
docs: fix WARNING document not included in any toctree 2026-03-04T12:19:43+00:00 SurajSonawane2415 surajsonawane0215@gmail.com 2024-10-02T19:58:17+00:00 b2f972293451061ffbdd63539b4be3ad55fbe715 [ Upstream commit 998bece1d22bf2cbc819cb3a492148932d4e12a8 ] Add debugging.rst to the relevant toctree to fix warning about missing documentation inclusion in toctree. Signed-off-by: SurajSonawane2415 <surajsonawane0215@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20241002195817.22972-1-surajsonawane0215@gmail.com Stable-dep-of: 8236fc613d44 ("Documentation: tracing: Add PCI tracepoint documentation") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 998bece1d22bf2cbc819cb3a492148932d4e12a8 ]

Add debugging.rst to the relevant toctree to fix warning
about missing documentation inclusion in toctree.

Signed-off-by: SurajSonawane2415 <surajsonawane0215@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241002195817.22972-1-surajsonawane0215@gmail.com
Stable-dep-of: 8236fc613d44 ("Documentation: tracing: Add PCI tracepoint documentation")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Documentation: tracing: Add ring-buffer mapping 2026-03-04T12:19:43+00:00 Vincent Donnefort vdonnefort@google.com 2024-05-10T14:04:33+00:00 bd43a6e857796b901c6378d34f8ad8c0540fd958 [ Upstream commit a1e0dd7ce38af3fb1a3bc54a222a7c5e4eaa4202 ] It is now possible to mmap() a ring-buffer to stream its content. Add some documentation and a code example. Link: https://lore.kernel.org/linux-trace-kernel/20240510140435.3550353-5-vdonnefort@google.com Signed-off-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Stable-dep-of: 8236fc613d44 ("Documentation: tracing: Add PCI tracepoint documentation") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit a1e0dd7ce38af3fb1a3bc54a222a7c5e4eaa4202 ]

It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.

Link: https://lore.kernel.org/linux-trace-kernel/20240510140435.3550353-5-vdonnefort@google.com

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Stable-dep-of: 8236fc613d44 ("Documentation: tracing: Add PCI tracepoint documentation")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Documentation: trace: historgram-design: Separate sched_waking histogram section heading and the following diagram 2025-10-15T09:58:02+00:00 Bagas Sanjaya bagasdotme@gmail.com 2025-09-16T05:42:01+00:00 12ff1858301e2e9da6cff5957f9ba5e3ce9c39d0 [ Upstream commit 8c716e87ea33519920811338100d6d8a7fb32456 ] Section heading for sched_waking histogram is shown as normal paragraph instead due to codeblock marker for the following diagram being in the same line as the section underline. Separate them. Fixes: daceabf1b494 ("tracing/doc: Fix ascii-art in histogram-design.rst") Reviewed-by: Tom Zanussi <zanussi@kernel.org> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Message-ID: <20250916054202.582074-5-bagasdotme@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 8c716e87ea33519920811338100d6d8a7fb32456 ]

Section heading for sched_waking histogram is shown as normal paragraph
instead due to codeblock marker for the following diagram being in the
same line as the section underline. Separate them.

Fixes: daceabf1b494 ("tracing/doc: Fix ascii-art in histogram-design.rst")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20250916054202.582074-5-bagasdotme@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Documentation: probes: Add a new ret_ip callback parameter 2023-10-17T01:21:45+00:00 Masami Hiramatsu (Google) mhiramat@kernel.org 2023-09-24T13:36:11+00:00 2a86ac30a6687e47436e547deadae3bf0fc28697 Add a new ret_ip callback parameter description. Link: https://lore.kernel.org/all/169556257133.146934.13560704846459957726.stgit@devnote2/ Fixes: cb16330d1274 ("fprobe: Pass return address to the handlers") Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Florent Revest <revest@chromium.org> 
Add a new ret_ip callback parameter description.

Link: https://lore.kernel.org/all/169556257133.146934.13560704846459957726.stgit@devnote2/

Fixes: cb16330d1274 ("fprobe: Pass return address to the handlers")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Florent Revest <revest@chromium.org>
Merge tag 'probes-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace 2023-09-02T18:10:50+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-09-02T18:10:50+00:00 b70100f2e62aeec2087d7690e41f7d6afd445f5a Pull probes updates from Masami Hiramatsu: - kprobes: use struct_size() for variable size kretprobe_instance data structure. - eprobe: Simplify trace_eprobe list iteration. - probe events: Data structure field access support on BTF argument. - Update BTF argument support on the functions in the kernel loadable modules (only loaded modules are supported). - Move generic BTF access function (search function prototype and get function parameters) to a separated file. - Add a function to search a member of data structure in BTF. - Support accessing BTF data structure member from probe args by C-like arrow('->') and dot('.') operators. e.g. 't sched_switch next=next->pid vruntime=next->se.vruntime' - Support accessing BTF data structure member from $retval. e.g. 'f getname_flags%return +0($retval->name):string' - Add string type checking if BTF type info is available. This will reject if user specify ":string" type for non "char pointer" type. - Automatically assume the fprobe event as a function return event if $retval is used. - selftests/ftrace: Add BTF data field access test cases. - Documentation: Update fprobe event example with BTF data field. * tag 'probes-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: Documentation: tracing: Update fprobe event example with BTF field selftests/ftrace: Add BTF fields access testcases tracing/fprobe-event: Assume fprobe is a return event by $retval tracing/probes: Add string type check with BTF tracing/probes: Support BTF field access from $retval tracing/probes: Support BTF based data structure field access tracing/probes: Add a function to search a member of a struct/union tracing/probes: Move finding func-proto API and getting func-param API to trace_btf tracing/probes: Support BTF argument on module functions tracing/eprobe: Iterate trace_eprobe directly kernel: kprobes: Use struct_size() 
Pull probes updates from Masami Hiramatsu:

 - kprobes: use struct_size() for variable size kretprobe_instance data
   structure.

 - eprobe: Simplify trace_eprobe list iteration.

 - probe events: Data structure field access support on BTF argument.

     - Update BTF argument support on the functions in the kernel
       loadable modules (only loaded modules are supported).

     - Move generic BTF access function (search function prototype and
       get function parameters) to a separated file.

     - Add a function to search a member of data structure in BTF.

     - Support accessing BTF data structure member from probe args by
       C-like arrow('->') and dot('.') operators. e.g.
          't sched_switch next=next->pid vruntime=next->se.vruntime'

     - Support accessing BTF data structure member from $retval. e.g.
          'f getname_flags%return +0($retval->name):string'

     - Add string type checking if BTF type info is available. This will
       reject if user specify ":string" type for non "char pointer"
       type.

     - Automatically assume the fprobe event as a function return event
       if $retval is used.

 - selftests/ftrace: Add BTF data field access test cases.

 - Documentation: Update fprobe event example with BTF data field.

* tag 'probes-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  Documentation: tracing: Update fprobe event example with BTF field
  selftests/ftrace: Add BTF fields access testcases
  tracing/fprobe-event: Assume fprobe is a return event by $retval
  tracing/probes: Add string type check with BTF
  tracing/probes: Support BTF field access from $retval
  tracing/probes: Support BTF based data structure field access
  tracing/probes: Add a function to search a member of a struct/union
  tracing/probes: Move finding func-proto API and getting func-param API to trace_btf
  tracing/probes: Support BTF argument on module functions
  tracing/eprobe: Iterate trace_eprobe directly
  kernel: kprobes: Use struct_size()
Merge tag 'trace-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace 2023-09-01T23:34:25+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-09-01T23:34:25+00:00 34232fcfe9a383bea802af682baae5c99f22376c Pull tracing updates from Steven Rostedt: "User visible changes: - Added a way to easier filter with cpumasks: # echo 'cpumask & CPUS{17-42}' > /sys/kernel/tracing/events/ipi_send_cpumask/filter - Show actual size of ring buffer after modifying the ring buffer size via buffer_size_kb. Currently it just returns what was written, but the actual size rounds up to the sub buffer size. Show that real size instead. Major changes: - Added "eventfs". This is the code that handles the inodes and dentries of tracefs/events directory. As there are thousands of events, and each event has several inodes and dentries that currently exist even when tracing is never used, they take up precious memory. Instead, eventfs will allocate the inodes and dentries in a JIT way (similar to what procfs does). There is now metadata that handles the events and subdirectories, and will create the inodes and dentries when they are used. Note, I also have patches that remove the subdirectory meta data, but will wait till the next merge window before applying them. It's a little more complex, and I want to make sure the dynamic code works properly before adding more complexity, making it easier to revert if need be. Minor changes: - Optimization to user event list traversal - Remove intermediate permission of tracefs files (note the intermediate permission removes all access to the files so it is not a security concern, but just a clean up) - Add the complex fix to FORTIFY_SOURCE to the kernel stack event logic - Other minor cleanups" * tag 'trace-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (29 commits) tracefs: Remove kerneldoc from struct eventfs_file tracefs: Avoid changing i_mode to a temp value tracing/user_events: Optimize safe list traversals ftrace: Remove empty declaration ftrace_enable_daemon() and ftrace_disable_daemon() tracing: Remove unused function declarations tracing/filters: Document cpumask filtering tracing/filters: Further optimise scalar vs cpumask comparison tracing/filters: Optimise CPU vs cpumask filtering when the user mask is a single CPU tracing/filters: Optimise scalar vs cpumask filtering when the user mask is a single CPU tracing/filters: Optimise cpumask vs cpumask filtering when user mask is a single CPU tracing/filters: Enable filtering the CPU common field by a cpumask tracing/filters: Enable filtering a scalar field by a cpumask tracing/filters: Enable filtering a cpumask field by another cpumask tracing/filters: Dynamically allocate filter_pred.regex test: ftrace: Fix kprobe test for eventfs eventfs: Move tracing/events to eventfs eventfs: Implement removal of meta data from eventfs eventfs: Implement functions to create files and dirs when accessed eventfs: Implement eventfs lookup, read, open functions eventfs: Implement eventfs file add functions ... 
Pull tracing updates from Steven Rostedt:
 "User visible changes:

   - Added a way to easier filter with cpumasks:

       # echo 'cpumask & CPUS{17-42}' > /sys/kernel/tracing/events/ipi_send_cpumask/filter

   - Show actual size of ring buffer after modifying the ring buffer
     size via buffer_size_kb.

     Currently it just returns what was written, but the actual size
     rounds up to the sub buffer size. Show that real size instead.

  Major changes:

   - Added "eventfs". This is the code that handles the inodes and
     dentries of tracefs/events directory. As there are thousands of
     events, and each event has several inodes and dentries that
     currently exist even when tracing is never used, they take up
     precious memory. Instead, eventfs will allocate the inodes and
     dentries in a JIT way (similar to what procfs does). There is now
     metadata that handles the events and subdirectories, and will
     create the inodes and dentries when they are used.

     Note, I also have patches that remove the subdirectory meta data,
     but will wait till the next merge window before applying them. It's
     a little more complex, and I want to make sure the dynamic code
     works properly before adding more complexity, making it easier to
     revert if need be.

  Minor changes:

   - Optimization to user event list traversal

   - Remove intermediate permission of tracefs files (note the
     intermediate permission removes all access to the files so it is
     not a security concern, but just a clean up)

   - Add the complex fix to FORTIFY_SOURCE to the kernel stack event
     logic

   - Other minor cleanups"

* tag 'trace-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (29 commits)
  tracefs: Remove kerneldoc from struct eventfs_file
  tracefs: Avoid changing i_mode to a temp value
  tracing/user_events: Optimize safe list traversals
  ftrace: Remove empty declaration ftrace_enable_daemon() and ftrace_disable_daemon()
  tracing: Remove unused function declarations
  tracing/filters: Document cpumask filtering
  tracing/filters: Further optimise scalar vs cpumask comparison
  tracing/filters: Optimise CPU vs cpumask filtering when the user mask is a single CPU
  tracing/filters: Optimise scalar vs cpumask filtering when the user mask is a single CPU
  tracing/filters: Optimise cpumask vs cpumask filtering when user mask is a single CPU
  tracing/filters: Enable filtering the CPU common field by a cpumask
  tracing/filters: Enable filtering a scalar field by a cpumask
  tracing/filters: Enable filtering a cpumask field by another cpumask
  tracing/filters: Dynamically allocate filter_pred.regex
  test: ftrace: Fix kprobe test for eventfs
  eventfs: Move tracing/events to eventfs
  eventfs: Implement removal of meta data from eventfs
  eventfs: Implement functions to create files and dirs when accessed
  eventfs: Implement eventfs lookup, read, open functions
  eventfs: Implement eventfs file add functions
  ...
Documentation: tracing: Update fprobe event example with BTF field 2023-08-23T00:42:08+00:00 Masami Hiramatsu (Google) mhiramat@kernel.org 2023-08-22T16:27:03+00:00 a2439a4c90856b83657aec4600c19551aa9501ff Update fprobe event example with BTF data structure field specification. Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> 
Update fprobe event example with BTF data structure field specification.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
tracing/filters: Document cpumask filtering 2023-08-22T09:13:29+00:00 Valentin Schneider vschneid@redhat.com 2023-07-07T17:21:55+00:00 fa828efb9cb3afae46163b02988fbb4fff1122bc Cpumask, scalar and CPU fields can now be filtered by a user-provided cpumask, document the syntax. Link: https://lkml.kernel.org/r/20230707172155.70873-10-vschneid@redhat.com Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Leonardo Bras <leobras@redhat.com> Cc: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Valentin Schneider <vschneid@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> 
Cpumask, scalar and CPU fields can now be filtered by a user-provided
cpumask, document the syntax.

Link: https://lkml.kernel.org/r/20230707172155.70873-10-vschneid@redhat.com

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Leonardo Bras <leobras@redhat.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>