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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.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>
Subject: Re: [PATCH 3/4] perf: Fix event leak upon exit
Message-ID: <20240606100851.QI7uQRSB@linutronix.de>
References: <20240516140936.13694-1-frederic@kernel.org>
 <20240516140936.13694-4-frederic@kernel.org>
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In-Reply-To: <20240516140936.13694-4-frederic@kernel.org>

On 2024-05-16 16:09:35 [+0200], Frederic Weisbecker wrote:
> When a task is scheduled out, pending sigtrap deliveries are deferred
> to the target task upon resume to userspace via task_work.
> 
> However failures while adding en event's callback to the task_work
                                an
> engine are ignored. And since the last call for events exit happen
> after task work is eventually closed, there is a small window during
> which pending sigtrap can be queued though ignored, leaking the event
> refcount addition such as in the following scenario:

Sebastian