Re: WARNING bisected (was Re: [PATCH v7 08/10] mm: rework non-root kmem_cache lifecycle management)

[Rik van Riel]

On Thu, 2019-11-21 at 13:45 -0500, Roman Gushchin wrote:
> On Thu, Nov 21, 2019 at 05:59:54PM +0100, Christian Borntraeger
> wrote:
> > 
> > 
> > Yes, rmmod has to be called directly after the guest shutdown to
> > see the issue.
> > See my 2nd mail.
> 
> I see. Do you know, which kmem_cache it is? If not, can you, please,
> figure it out?
> 
> I tried to reproduce the issue, but wasn't successful so far. So I
> wonder
> what can make your case special.

I do not know either, but have a guess.

My guess would be that either the slab object or the
slab page is RCU freed, and the kmem_cache destruction
is called before that RCU callback has completed.