From: Petr Mladek <pmladek@suse.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Martin Liu <liumartin@google.com>,
Oleg Nesterov <oleg@redhat.com>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Tejun Heo <tj@kernel.org>,
minchan@google.com, davidchao@google.com, jenhaochen@google.com,
clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] kthread: Prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync()
Date: Mon, 14 Jun 2021 09:10:12 +0200 [thread overview]
Message-ID: <YMcA1BL5RVRm25bu@alley> (raw)
In-Reply-To: <20210611134125.bdb08ba0d2b6b87dc60d446d@linux-foundation.org>
On Fri 2021-06-11 13:41:25, Andrew Morton wrote:
> On Fri, 11 Jun 2021 09:16:52 +0200 Petr Mladek <pmladek@suse.com> wrote:
>
> > On Thu 2021-06-10 14:30:30, Andrew Morton wrote:
> > > On Thu, 10 Jun 2021 15:30:50 +0200 Petr Mladek <pmladek@suse.com> wrote:
> > >
> > > > The system might hang with the following backtrace:
> > >
> > > Well that's not good.
> >
> > Fortunately, the API users normally synchronize these operations
> > another way. The race should never happen when the API is used
> > a reasonable way,
> > see https://lore.kernel.org/lkml/YKZLnTNOlUQ85F2s@alley/
> >
> > > > Fixes: 9a6b06c8d9a220860468a ("kthread: allow to modify delayed kthread work")
> > > > Reported-by: Martin Liu <liumartin@google.com>
> > > > Signed-off-by: Petr Mladek <pmladek@suse.com>
> > >
> > > Was a -stable backport considered?
> >
> > Good point! It would make sense to backport it. System hang is never
> > good.
> >
> > Could you please add Cc: stable@vger.kernel.org or should I resend the
> > patchset?
>
> I made that change to patches 1&2. I don't think patch 3 need be
> backported?
Sounds good to me. Thanks a lot for the update.
Best Regards,
Petr
next prev parent reply other threads:[~2021-06-14 7:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-10 13:30 [PATCH 0/3] kthread_worker: Fix race between kthread_mod_delayed_work() and kthread_cancel_delayed_work_sync() Petr Mladek
2021-06-10 13:30 ` [PATCH 1/3] kthread_worker: Split code for canceling the delayed work timer Petr Mladek
2021-06-10 13:30 ` [PATCH 2/3] kthread: Prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync() Petr Mladek
2021-06-10 21:30 ` Andrew Morton
2021-06-11 7:16 ` Petr Mladek
2021-06-11 20:41 ` Andrew Morton
2021-06-14 7:10 ` Petr Mladek [this message]
2021-06-10 13:30 ` [PATCH 3/3] kthread_worker: Fix return value " Petr Mladek
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=YMcA1BL5RVRm25bu@alley \
--to=pmladek@suse.com \
--cc=akpm@linux-foundation.org \
--cc=clang-built-linux@googlegroups.com \
--cc=davidchao@google.com \
--cc=jenhaochen@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=liumartin@google.com \
--cc=minchan@google.com \
--cc=nathan@kernel.org \
--cc=ndesaulniers@google.com \
--cc=oleg@redhat.com \
--cc=tj@kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.