On Thu, Nov 21, 2019 at 12:43:01PM -0800, Rik van Riel wrote: > 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. > I've a reproducer, but it requires SLAB_TYPESAFE_BY_RCU to panic. The only question is if it's the same or different issues. As soon as I'll have a fix, I'll post it here to test. Thanks!