Re: [PATCH?] race between cgroup_subsys->fork() and cgroup_migrate()

Tejun Heo
2015-11-25T20:41:08Z

On Wed, Nov 25, 2015 at 02:54:10PM -0500, Tejun Heo wrote:
> On Wed, Nov 25, 2015 at 02:51:38PM -0500, Tejun Heo wrote:
> > Sounds perfect. As this needs to go through -stable, can you please
> > resend the patch with proper description and SOB? Please also update
> > the now incorrect comment in can_attach.
>
> Ooh, the patch triggers RCU warning from task_css(). It's spurious
> and I think the right thing to do at least for now is using
> task_css_check() and explain what's going on.

And I spotted a bug in cgroup core in controller enable path. While
the race between fork and attach exists and needs to be fixed, I think
the cgroup core bug is the main source of discrepancy. Will update
once I learn more.

Thanks.

--
tejun