From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Tengda Wu <wutengda@huaweicloud.com>
Cc: 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>,
James Clark <james.clark@linaro.org>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf/core: Prevent duplicate sigtrap task work enqueue
Date: Mon, 2 Nov 2026 17:35:40 +0100 [thread overview]
Message-ID: <20261102163540.4WF7hhhW@linutronix.de> (raw)
In-Reply-To: <20261031114520.642476-1-wutengda@huaweicloud.com>
On 2026-10-31 11:45:20 [+0000], Tengda Wu wrote:
> The sigtrap handling in __perf_event_overflow() checks
> event->pending_work before calling task_work_add(), but only sets
> pending_work after the task work has been queued.
>
> This leaves a window where an NMI can interrupt task_work_add()
> and re-enter __perf_event_overflow() for the same event. Since
> pending_work is still zero, the nested invocation can enqueue
> the same pending_task again.
>
> The re-entrant call path is:
>
> __perf_event_overflow()
> task_work_add()
> kasan_record_aux_stack()
> <NMI>
> __perf_event_overflow()
> task_work_add()
How was the issue identified?
Sebastian
next prev parent reply other threads:[~2026-11-02 16:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-31 11:45 Tengda Wu
2026-11-02 16:35 ` Sebastian Andrzej Siewior [this message]
2026-11-03 1:21 ` Tengda Wu
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