From: Miroslav Benes <mbenes@suse.cz>
To: Yafang Shao <laoar.shao@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>,
jpoimboe@kernel.org, jikos@kernel.org, joe.lawrence@redhat.com,
live-patching@vger.kernel.org
Subject: Re: [PATCH] livepatch: Avoid hard lockup caused by klp_try_switch_task()
Date: Fri, 31 Jan 2025 14:06:38 +0100 (CET) [thread overview]
Message-ID: <alpine.LSU.2.21.2501311405280.10231@pobox.suse.cz> (raw)
In-Reply-To: <CALOAHbCw5_ZxNuRkwzMqz7NFdnJWgt-n4R--oYiE+BtNGP_8aw@mail.gmail.com>
Hi,
> $ cat log | grep do_exit | wc -l
> 1061
>
> It seems that there are simply too many threads executing do_exit() at
> the moment.
>
> >
> > You might try to use printk_deferred() instead. Also you might need
> > to disable interrupts around the read_lock()/read_unlock() to
> > make sure that the console handling will be deferred after
> > the tasklist_lock gets released.
> >
> > Anyway, I am against this patch.
>
> However, there is still a risk of triggering a hard lockup if a large
> number of tasks are involved.
And as Petr said, it is very likely caused by pr_debug() in this setup.
The proposed patch is not a fix and would make things only worse.
Regards,
Miroslav
next prev parent reply other threads:[~2025-01-31 13:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-22 8:51 [PATCH] livepatch: Avoid hard lockup caused by klp_try_switch_task() Yafang Shao
2025-01-22 12:50 ` Petr Mladek
2025-01-22 13:46 ` Yafang Shao
2025-01-31 13:06 ` Miroslav Benes [this message]
2025-01-31 13:22 ` zhang warden
2025-01-31 13:39 ` Petr Mladek
2025-02-01 2:04 ` zhang warden
2025-02-05 8:39 ` Yafang Shao
2025-02-06 16:43 ` Petr Mladek
2025-02-07 2:16 ` Yafang Shao
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.LSU.2.21.2501311405280.10231@pobox.suse.cz \
--to=mbenes@suse.cz \
--cc=jikos@kernel.org \
--cc=joe.lawrence@redhat.com \
--cc=jpoimboe@kernel.org \
--cc=laoar.shao@gmail.com \
--cc=live-patching@vger.kernel.org \
--cc=pmladek@suse.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox