Re: [PATCH v2] mm/page_isolation: fix a deadlock with printk()

Michal Hocko
2019-10-08T10:39:16Z

On Tue 08-10-19 06:04:32, Qian Cai wrote:
>
>
> > On Oct 8, 2019, at 4:40 AM, Michal Hocko <mhocko@kernel.org> wrote:
> >
> > Does this tip point to a real deadlock or merely a class of lockdep
> > false dependencies?
>
> I lean towards it is a real deadlock given how trivial to generate those lock orders everywhere.

Have you actually triggered any real deadlock? With a zone->lock in
place it would be pretty clear with hard lockups detected.

--
Michal Hocko
SUSE Labs