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Date: Wed, 5 Mar 2025 15:56:22 +0100
From: Frederic Weisbecker <frederic@kernel.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	"Liang, Kan" <kan.liang@linux.intel.com>,
	Oleg Nesterov <oleg@redhat.com>, Yi Lai <yi1.lai@linux.intel.com>,
	syzbot+3c4321e10eea460eb606@syzkaller.appspotmail.com
Subject: Re: [PATCH] perf: Fix hang while freeing sigtrap event
Message-ID: <Z8hmFhg5g7n3JKXP@localhost.localdomain>
References: <20250304135446.18905-1-frederic@kernel.org>
 <20250305081907.xHiR7jy0@linutronix.de>
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In-Reply-To: <20250305081907.xHiR7jy0@linutronix.de>

Le Wed, Mar 05, 2025 at 09:19:07AM +0100, Sebastian Andrzej Siewior a écrit :
> On 2025-03-04 14:54:46 [+0100], Frederic Weisbecker wrote:
> > Perf can hang while freeing a sigtrap event if a related deferred
> > signal hadn't managed to be sent before the file got closed:
> …
> > Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> 
> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> 
> Both of the test cases pass… This looks way simpler than the initial
> attempts, why didn't we go with this initially?

Because I was afraid that a pending perf signal queued before or during
exec may be delivered later to an suid process. But eventually I don't see
anything that prevented from that even before this patch.

Thanks.