Re: proc_flush_task oops

From: Dave Jones
Date: Wed Dec 20 2017 - 22:16:20 EST

On Wed, Dec 20, 2017 at 12:25:52PM -0600, Eric W. Biederman wrote:
> > >
> > > If the warning triggers it means the bug is in alloc_pid and somehow
> > > something has gotten past the is_child_reaper check.
> >
> > You're onto something.
> >
> I am not seeing where things go wrong, but that puts the recent pid bitmap, bit
> hash to idr change in the suspect zone.
> Can you try reverting that change:
> e8cfbc245e24 ("pid: remove pidhash")
> 95846ecf9dac ("pid: replace pid bitmap implementation with IDR API")
> While keeping the warning in place so we can see if this fixes the
> allocation problem?

So I can't trigger this any more with those reverted. I seem to hit a
bunch of other long-standing bugs first. I'll keep running it
overnight, but it looks like this is where the problem lies.