On Wed, Aug 10, 2016 at 10:42:09AM +0200, Roman Penyaev wrote: > Hi, > > On Wed, Aug 10, 2016 at 5:55 AM, Tejun Heo <t...@kernel.org> wrote: > > Hello, > > > > On Mon, Aug 08, 2016 at 01:39:08PM +0200, Roman Pen wrote: > >> Long time ago there was a similar fix proposed by Akinobu Mita[1], > >> but it seems that time everyone decided to fix this subtle race in > >> percpu-refcount and Tejun Heo[2] did an attempt (as I can see that > >> patchset was not applied). > > > > So, I probably forgot about it while waiting for confirmation of fix. > > Can you please verify that the patchset fixes the issue? I can apply > > the patchset right away. > > I have not checked your patchset but according to my understanding > it should not fix *this* issue. What happens here is a wrong order > of invocation of percpu_ref_reinit() and percpu_ref_kill(). So what > was observed is the following:
Ah, understood. Acked-by: Tejun Heo <t...@kernel.org> I'll commit the percpu_refcnt patches too. While they don't fix the problem on their own, the changes are generally useful for all mode switching use cases. Thanks. -- tejun
