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.