linux-kernel - Re: [PATCH 0/4] perf: Fix leaked events when sigtrap = 1

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Date: Fri, 29 Mar 2024 20:23:49 -0700
From: Ian Rogers <irogers@...gle.com>
To: Frederic Weisbecker <frederic@...nel.org>
Cc: LKML <linux-kernel@...r.kernel.org>, Peter Zijlstra <peterz@...radead.org>, 
	Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>
Subject: Re: [PATCH 0/4] perf: Fix leaked events when sigtrap = 1

On Fri, Mar 29, 2024 at 4:58 PM Frederic Weisbecker <frederic@...nel.org> wrote:
>
> While looking at task_work users I just noticed that perf doesn't flush
> its own upon event exiting. This looks especially problematic with child
> events. Please have a thourough look at the last patch, I may easily
> have missed something within the maze.
>
> Frederic Weisbecker (4):
>   task_work: s/task_work_cancel()/task_work_cancel_func()/
>   task_work: Introduce task_work_cancel() again
>   perf: Fix event leak upon exit
>   perf: Fix event leak upon exec and file release
>
>  include/linux/perf_event.h |  1 +
>  include/linux/task_work.h  |  3 ++-
>  kernel/events/core.c       | 40 +++++++++++++++++++++++++++++++-------
>  kernel/irq/manage.c        |  2 +-
>  kernel/task_work.c         | 34 +++++++++++++++++++++++++++-----
>  security/keys/keyctl.c     |  2 +-
>  6 files changed, 67 insertions(+), 15 deletions(-)

Thanks for this! I wonder if this relates to fuzzing failures like:
https://lore.kernel.org/linux-perf-users/CAP-5=fUa+-Tj2b_hxk96Qg5=Qu7jYHgHREbsmBa2ZmuF-X9QaA@mail.gmail.com/
"[ 2519.138665] unexpected event refcount: 2; ptr=000000009c56b097"

Thanks,
Ian

> --
> 2.44.0
>