linux-kernel - Re: [PATCH v3 1/2] Allow cpu backtraces to be written into ringbuffer during panic

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: <ZrtkMciiYhUK8Fs4@pathway.suse.cz>
Date: Tue, 13 Aug 2024 15:48:33 +0200
From: Petr Mladek <pmladek@...e.com>
To: takakura@...inux.co.jp
Cc: rostedt@...dmis.org, john.ogness@...utronix.de,
	senozhatsky@...omium.org, akpm@...ux-foundation.org, bhe@...hat.com,
	lukas@...ner.de, wangkefeng.wang@...wei.com, ubizjak@...il.com,
	feng.tang@...el.com, j.granados@...sung.com,
	stephen.s.brennan@...cle.com, linux-kernel@...r.kernel.org,
	nishimura@...inux.co.jp, taka@...inux.co.jp
Subject: Re: [PATCH v3 1/2] Allow cpu backtraces to be written into
 ringbuffer during panic

On Mon 2024-08-12 16:27:03, takakura@...inux.co.jp wrote:
> From: Ryo Takakura <takakura@...inux.co.jp>
> 
> commit 779dbc2e78d7 ("printk: Avoid non-panic CPUs writing
> to ringbuffer") disabled non-panic CPUs to further write messages to
> ringbuffer after panicked.
> 
> Since the commit, non-panicked CPU's are not allowed to write to
> ring buffer after panicked and CPU backtrace which is triggered
> after panicked to sample non-panicked CPUs' backtrace no longer
> serves its function as it has nothing to print.
> 
> Fix the issue by allowing non-panicked CPUs to write into ringbuffer
> while CPU backtrace is in flight.
> 
> Fixes: 779dbc2e78d7 ("printk: Avoid non-panic CPUs writing to ringbuffer")
> Signed-off-by: Ryo Takakura <takakura@...inux.co.jp>
> Reviewed-by: Petr Mladek <pmladek@...e.com>

JFYI, I have pushed this patch into printk/linux.git, branch for-6.11-fixup.
I am going to create pull request after it spends at least one or two
days in linux-next.

The 2nd patch is more complicated. It depends on another patchset
integrating con->write_atomic() callback. 

Best Regards,
Petr