Re: [PATCH] workqueue: fix selection of wake_cpu in kick_pool()

From: Tejun Heo
Date: Thu Apr 18 2024 - 11:56:26 EST


On Thu, Apr 18, 2024 at 07:54:37AM +0200, Sven Schnelle wrote:
> Tejun Heo <tj@xxxxxxxxxx> writes:
>
> > Hello,
> >
> > On Wed, Apr 17, 2024 at 05:36:38PM +0200, Sven Schnelle wrote:
> >> > This generally seems like a good idea but isn't this still racy? The CPU may
> >> > go down between setting p->wake_cpu and wake_up_process().
> >>
> >> Don't know without reading the source, but how does this code normally
> >> protect against that?
> >
> > Probably by wrapping determining the wake_cpu and the wake_up inside
> > cpu_read_lock() section.
>
> Thanks. Should i send a v2 and incorporate your additional changes or do
> you want to do that?

Yes, please send a v2.

Thanks.

--
tejun