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

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Message-ID: <ZhRaizXTwxpe_bm_@pavilion.home>
Date: Mon, 8 Apr 2024 22:58:51 +0200
From: Frederic Weisbecker <frederic@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Ian Rogers <irogers@...gle.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>, 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>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-perf-users@...r.kernel.org
Subject: Re: [PATCH 0/4] perf: Fix leaked events when sigtrap = 1

Le Mon, Apr 08, 2024 at 05:20:27PM -0300, Arnaldo Carvalho de Melo a écrit :
> On Mon, Apr 08, 2024 at 09:43:41PM +0200, Frederic Weisbecker wrote:
> > Le Fri, Mar 29, 2024 at 08:23:49PM -0700, Ian Rogers a écrit :
> > > 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"
> > 
> > Probably not since those seem to happen on perf_event_open() failures. This
> > looks different.
> 
> Probably clashes with this one?
> 
> "[PATCH v3 0/4] perf: Make SIGTRAP and __perf_pending_irq() work on RT."
> 
> https://lore.kernel.org/all/20240322065208.60456-1-bigeasy@linutronix.de/T/#u

Nice, I think it partially fixes the issues I've seen. Lemme review that.

Thanks.

> 
> - Arnaldo