Re: [PATCH 2/3] kthread: Prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync()

[Petr Mladek]

On Thu 2021-06-10 14:30:30, Andrew Morton wrote:
> On Thu, 10 Jun 2021 15:30:50 +0200 Petr Mladek <pmladek@xxxxxxxx> 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@xxxxxxxxxx>
> > Signed-off-by: Petr Mladek <pmladek@xxxxxxxx>
> 
> 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@xxxxxxxxxxxxxxx or should I resend the
patchset?

Best Regards,
Petr