Hello.
On úterý 22. června 2021 18:47:59 CEST Greg KH wrote:
> On Tue, Jun 22, 2021 at 06:30:46PM +0200, Oleksandr Natalenko wrote:
> > I'd like to nominate d583d360a6 ("psi: Fix psi state corruption when
> > schedule() races with cgroup move") for 5.12 stable tree.
> >
> > Recently, I've hit this:
> >
> > ```
> > kernel: psi: inconsistent task state! task=2667:clementine cpu=21
> > psi_flags=0 clear=1 set=0
> > ```
> >
> > and after that PSI IO went crazy high. That seems to match the symptoms
> > described in the commit message.
>
> But this says it fixes 4117cebf1a9f ("psi: Optimize task switch inside
> shared cgroups") which did not show up until 5.13-rc1, so how are you
> hitting this issue?
I'm not positive 4117cebf1a9f was a root cause of the race. To me it looks
like 4117cebf1a9f just made an older issue more likely to be hit.
Peter, Johannes, am I correct saying that it is still possible to hit a
corruption described in d583d360a6 on 5.12?
> Did you try this patch on 5.12.y and see that it solved your problem?
Yes, I've built the kernel with this patch, and so far it runs fine. It can
take a while until the condition is hit though since it seems to be very
unlikely on 5.12.
--
Oleksandr Natalenko (post-factum)
