Re: rwsem exit_to_usermode

From: Oleg Nesterov
Date: Thu Feb 11 2016 - 15:04:34 EST


On 02/10, Andy Lutomirski wrote:
>
> On Wed, Feb 10, 2016 at 5:05 PM, Justin Capella <justincapella@xxxxxxxxx> wrote:
> > http://i.imgur.com/gKamNV3.jpg
> >
> > I encountered this deadlock situation, let me know if there is additional
> > info I can provide, if you're interested...
>
> You're the second person in 24 hours to privately report a bug in that code :-/

Let me add lkml,

> This looks like it's a signal thing, not an entry/exit thing, though.

Looks like someone holds cgroup_threadgroup_rwsem for writing.

Which kernel version? It would be nice to look at sysrq-T output...

Oleg.