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

Michal Hocko
2019-10-08T19:17:33Z

On Tue 08-10-19 15:06:13, Qian Cai wrote:
> On Tue, 2019-10-08 at 20:35 +0200, Michal Hocko wrote:
[...]
> > I fully agree that this class of lockdep splats are annoying especially
> > when they make the lockdep unusable but please discuss this with lockdep
> > maintainers and try to find some solution rather than go and try to
> > workaround the problem all over the place. If there are places that
> > would result in a cleaner code then go for it but please do not make the
> > code worse just because of a non existent problem flagged by a false
> > positive.
>
> It makes me wonder what make you think it is a false positive for sure.

Because this is an early init code? Because if it were a real deadlock
then your system wouldn't boot to get run with the real userspace
(remember there is zone->lock spinlock involved and that means that you
would hit hard lock after few seconds - but I feel I am repeating
myself).
--
Michal Hocko
SUSE Labs