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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1f4a84e5.32ca.19730d781aa.Coremail.00107082@163.com>
Date: Mon, 2 Jun 2025 21:31:59 +0800 (CST)
From: "David Wang" <00107082@....com>
To: "Yeoreum Yun" <yeoreum.yun@....com>
Cc: 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


At 2025-06-02 21:19:11, "Yeoreum Yun" <yeoreum.yun@....com> wrote:
>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

Am I reading it wrong? 
The call chain I mentioned above dose not walk through __perf_remove_from_context,
It is a fail path in fork, which happens rarely, but still possible. I guess...

David