linux-kernel - Re: [BUG][6.15][perf] Kernel panic not syncing: Fatal exception in interrupt

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Message-ID: <aD2kz52p5NHpuXk3@e129823.arm.com>
Date: Mon, 2 Jun 2025 14:19:11 +0100
From: Yeoreum Yun <yeoreum.yun@....com>
To: 83b4d26.3362.19730a21115.Coremail.00107082@....com
Cc: 00107082@....com, peterz@...radead.org, mingo@...hat.com,
	acme@...nel.org, namhyung@...nel.org, mingo@...nel.org,
	leo.yan@....com, linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [BUG][6.15][perf] Kernel panic not syncing: Fatal exception in
 interrupt

Hi David,

> Before I start testing, I feel concerned about following chain:
>
> ./kernel/fork.c:
> bad_fork_cleanup_perf:
>     perf_event_free_task()
>         perf_free_event()
>             list_del_event()
>
> This patch seems changes the behavior in this callchain.
> Would this have other side-effect?

What behavior is changed you're worry about?
both error patch is handled by __perf_remove_from_context(),
There wouldn't be no problem since this patch just move the
time of disabling cgroup before changing event state.

also, the cgroup event is for only cpuctx not added in taskctx.
So, there's no effect for event attached in taskctx.

Thanks.

--
Sincerely,
Yeoreum Yun