From: Liangyan <liangyan.peng@bytedance.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Liangyan <liangyan.peng@bytedance.com>
Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
namhyung@kernel.org, mark.rutland@arm.com,
alexander.shishkin@linux.intel.com, jolsa@kernel.org,
irogers@google.com, adrian.hunter@intel.com,
james.clark@linaro.org, zengxianjun@bytedance.com,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [External] Re: [PATCH v2] perf/core: Fix pending work re-queued in __perf_event_overflow
Date: Wed, 12 Nov 2025 11:28:05 +0800 [thread overview]
Message-ID: <b079b4f1-4d11-4137-8204-16935dc12129@google.com> (raw)
In-Reply-To: <20251111133023.YqDNgQak@linutronix.de>
On 2025/11/11 21:30, Sebastian Andrzej Siewior wrote:
> On 2025-11-10 00:41:22 [+0800], Liangyan wrote:
>> We got warning below during perf test.
> …
>>
>> A race condition occurs between task context and IRQ context when
>> handling sigtrap tracepoint event overflows:
>>
>> 1. In task context, an event is overflowed and its pending work is
>> queued to task->task_works
>> 2. Before pending_work is set, the same event overflows in IRQ context
>> 3. Both contexts queue the same perf pending work to task->task_works
>>
>> This double queuing causes:
>> - task_work_run() enters infinite loop calling perf_pending_task()
>> - Potential warnings and use-after-free when event is freed in
>> perf_pending_task()
>>
>> Fix the race by disabling interrupts during queuing of perf pending work.
>
> Makes sense. Lets it does not overflow in NMI, too.
> Either way I suggest to trim the commit message and remove the
> backtrace as it probably does not add any value.
>
> Sebastian
Got it, I will remove the backtrace in the following version.
next prev parent reply other threads:[~2025-11-12 3:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-09 10:32 [PATCH] " Liangyan
2025-11-09 11:45 ` Peter Zijlstra
2025-11-09 16:41 ` [PATCH v2] " Liangyan
2025-11-11 13:30 ` Sebastian Andrzej Siewior
2025-11-12 3:28 ` Liangyan [this message]
2025-11-14 3:33 ` [PATCH v3] " Liangyan
2025-11-14 8:02 ` Sebastian Andrzej Siewior
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