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* [for-linus][PATCH 0/5] tracing: Fixes for 7.0
@ 2026-03-22  3:09 Steven Rostedt
  2026-03-22  3:09 ` [for-linus][PATCH 1/5] tracing: Revert "tracing: Remove pid in task_rename tracing output" Steven Rostedt
                   ` (4 more replies)
  0 siblings, 5 replies; 7+ messages in thread
From: Steven Rostedt @ 2026-03-22  3:09 UTC (permalink / raw)
  To: linux-kernel
  Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton


tracing fixes for 7.0:

- Revert "tracing: Remove pid in task_rename tracing output"

  A change was made to remove the pid field from the task_rename event
  because it was thought that it was always done for the current task and
  recording the pid would be redundant. This turned out to be incorrect and
  there are a few corner casse where this is not true and caused some
  regressions in tooling.

- Fix the reading from user space for migration

  The reading of user space uses a seq lock type of logic where it uses a
  per-cpu temporary buffer and disables migration, then enables preemption,
  does the copy from user space, disables preemption, enables migration and
  checks if there was any schedule switches while preemption was enabled. If
  there was a context switch, then it is considered that the per-cpu buffer
  could be corrupted and it tries again. There's a protection check that
  tests if it takes a hundred tries it issues a warning and exits out to
  prevent a live lock.

  This was triggered because the task was selected by the load balancer to
  be migrated to another CPU, every time preemption is enabled the migration
  task would schedule in try to migrate the task but can't because migration
  is enabled and let it run again. This caused the scheduler to schedule out
  the task every time it enabled preemption and made the loop never exit
  (until the 100 iteration test triggered).

  Fix this by enabling and disabling preemption and keeping migration
  enabled on a failure. This will let the migration thread to migrate the
  task and the copy from user space will likely pass on the next iteration.

- Fix trace_marker copy option freeing

  The "copy_trace_marker" option allows an tracing instance to get a copy of
  a write to the trace_marker file of the top level instance. This is
  managed by a link list protected by RCU. When an instance is removed, a
  check is made if the option is set, and if so synchronized_rcu() is
  called. The problem is that an iteration is made to reset all the flags to
  what they were when the instance was created (to perform clean ups) was
  done before the check of the copy_trace_marker option and that option was
  cleared, so the synchronize_rcu() was never called.

  Move the clearing of all the flags after the check of copy_trace_marker to
  do synchronize_rcu() so that the option is still set if it was before and
  the synchronization is performed.

- Fix entries setting when validating the persistent ring buffer

  When validating the persistent ring buffer on boot up, the number of
  events per sub-buffer is added to the sub-buffer meta page. The validator
  was updating cpu_buffer->head_page (the first sub-buffer of the per-cpu
  buffer) and not the "head_page" variable that was iterating the
  sub-buffers. This was causing the first sub-buffer to be assigned the
  entries for each sub-buffer and not the sub-buffer that was supposed to be
  updated.

- Use "hash" value to update the direct callers

  When updating the ftrace direct direct callers it assigned a temporary
  callback to all the callback functions of the ftrace ops and not just the
  functions represented by the passed in hash. This causes an unnecessary
  slow down of the functions of the ftrace_ops that is not being modified.
  Only update the functions that are going to be modified to call the ftrace
  loop function so that the update can be made on those functions.

  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
trace/fixes

Head SHA1: 50b35c9e50a865600344ab1d8f9a8b3384d7e63d


Jiri Olsa (1):
      ftrace: Use hash argument for tmp_ops in update_ftrace_direct_mod

Masami Hiramatsu (Google) (1):
      ring-buffer: Fix to update per-subbuf entries of persistent ring buffer

Steven Rostedt (2):
      tracing: Fix failure to read user space from system call trace events
      tracing: Fix trace_marker copy link list updates

Xuewen Yan (1):
      tracing: Revert "tracing: Remove pid in task_rename tracing output"

----
 include/trace/events/task.h |  7 +++++--
 kernel/trace/ftrace.c       |  4 ++--
 kernel/trace/ring_buffer.c  |  2 +-
 kernel/trace/trace.c        | 36 +++++++++++++++++++++++++++---------
 4 files changed, 35 insertions(+), 14 deletions(-)

^ permalink raw reply	[flat|nested] 7+ messages in thread
* [for-linus][PATCH 0/5] tracing: Fixes for 7.0
@ 2026-02-19 20:49 Steven Rostedt
  0 siblings, 0 replies; 7+ messages in thread
From: Steven Rostedt @ 2026-02-19 20:49 UTC (permalink / raw)
  To: linux-kernel
  Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton


Tracing fixes for 7.0:

- Fix possible dereference of uninitialized pointer

  When validating the persistent ring buffer on boot up, if the first
  validation fails, a reference to "head_page" is performed in the 
  error path, but it skips over the initialization of that variable.
  Move the initialization before the first validation check.

- Fix use of event length in validation of persistent ring buffer

  On boot up, the persistent ring buffer is checked to see if it is
  valid by several methods. One being to walk all the events in the
  memory location to make sure they are all valid. The length of the
  event is used to move to the next event. This length is determined
  by the data in the buffer. If that length is corrupted, it could
  possibly make the next event to check located at a bad memory location.

  Validate the length field of the event when doing the event walk.

- Fix function graph on archs that do not support use of ftrace_ops

  When an architecture defines HAVE_DYNAMIC_FTRACE_WITH_ARGS, it means
  that its function graph tracer uses the ftrace_ops of the function
  tracer to call its callbacks. This allows a single registered callback
  to be called directly instead of checking the callback's meta data's
  hash entries against the function being traced.

  For architectures that do not support this feature, it must always
  call the loop function that tests each registered callback (even if
  there's only one). The loop function tests each callback's meta data
  against its hash of functions and will call its callback if the
  function being traced is in its hash map.

  The issue was that there was no check against this and the direct
  function was being called even if the architecture didn't support it.
  This meant that if function tracing was enabled at the same time
  as a callback was registered with the function graph tracer, its
  callback would be called for every function that the function tracer
  also traced, even if the callback's meta data only wanted to be
  called back for a small subset of functions.

  Prevent the direct calling for those architectures that do not support
  it.

- Fix references to trace_event_file for hist files

  The hist files used event_file_data() to get a reference to the
  associated trace_event_file the histogram was attached to. This
  would return a pointer even if the trace_event_file is about to
  be freed (via RCU). Instead it should use the event_file_file()
  helper that returns NULL if the trace_event_file is marked to be
  freed so that no new references are added to it.

- Wake up hist poll readers when an event is being freed

  When polling on a hist file, the task is only awoken when a hist
  trigger is triggered. This means that if an event is being freed
  while there's a task waiting on its hist file, it will need to wait
  until the hist trigger occurs to wake it up and allow the freeing
  to happen. Note, the event will not be completely freed until all
  references are removed, and a hist poller keeps a reference. But
  it should still be woken when the event is being freed. 

  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
trace/fixes

Head SHA1: 9678e53179aa7e907360f5b5b275769008a69b80


Daniil Dulov (1):
      ring-buffer: Fix possible dereference of uninitialized pointer

Masami Hiramatsu (Google) (1):
      tracing: ring-buffer: Fix to check event length before using

Petr Pavlu (2):
      tracing: Fix checking of freed trace_event_file for hist files
      tracing: Wake up poll waiters for hist files when removing an event

Steven Rostedt (1):
      fgraph: Do not call handlers direct when not using ftrace_ops

----
 include/linux/ftrace.h           | 13 ++++++++++---
 include/linux/trace_events.h     |  5 +++++
 kernel/trace/fgraph.c            | 12 +++++++++++-
 kernel/trace/ring_buffer.c       |  9 +++++++--
 kernel/trace/trace_events.c      |  3 +++
 kernel/trace/trace_events_hist.c |  4 ++--
 6 files changed, 38 insertions(+), 8 deletions(-)

^ permalink raw reply	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2026-03-22  3:09 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
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2026-03-22  3:09 [for-linus][PATCH 0/5] tracing: Fixes for 7.0 Steven Rostedt
2026-03-22  3:09 ` [for-linus][PATCH 1/5] tracing: Revert "tracing: Remove pid in task_rename tracing output" Steven Rostedt
2026-03-22  3:09 ` [for-linus][PATCH 2/5] tracing: Fix failure to read user space from system call trace events Steven Rostedt
2026-03-22  3:09 ` [for-linus][PATCH 3/5] tracing: Fix trace_marker copy link list updates Steven Rostedt
2026-03-22  3:09 ` [for-linus][PATCH 4/5] ring-buffer: Fix to update per-subbuf entries of persistent ring buffer Steven Rostedt
2026-03-22  3:09 ` [for-linus][PATCH 5/5] ftrace: Use hash argument for tmp_ops in update_ftrace_direct_mod Steven Rostedt
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2026-02-19 20:49 [for-linus][PATCH 0/5] tracing: Fixes for 7.0 Steven Rostedt

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