From: Roman Gushchin <guro@fb.com>
To: Rik van Riel <riel@fb.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"hannes@cmpxchg.org" <hannes@cmpxchg.org>,
Kernel Team <Kernel-team@fb.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"longman@redhat.com" <longman@redhat.com>,
"shakeelb@google.com" <shakeelb@google.com>,
"vdavydov.dev@gmail.com" <vdavydov.dev@gmail.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Janosch Frank <frankja@linux.ibm.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: WARNING bisected (was Re: [PATCH v7 08/10] mm: rework non-root kmem_cache lifecycle management)
Date: Thu, 21 Nov 2019 20:55:27 +0000 [thread overview]
Message-ID: <20191121205520.GA5815@localhost.localdomain> (raw)
In-Reply-To: <30a2e4babdcb22974a0a5ae8c5e764d951eef7dc.camel@fb.com>
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!
next prev parent reply other threads:[~2019-11-21 20:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190611231813.3148843-9-guro@fb.com>
2019-11-21 11:17 ` WARNING bisected (was Re: [PATCH v7 08/10] mm: rework non-root kmem_cache lifecycle management) Christian Borntraeger
2019-11-21 13:08 ` Christian Borntraeger
2019-11-21 16:58 ` Roman Gushchin
2019-11-21 16:59 ` Christian Borntraeger
2019-11-21 18:45 ` Roman Gushchin
2019-11-21 20:43 ` Rik van Riel
2019-11-21 20:55 ` Roman Gushchin [this message]
2019-11-21 22:09 ` Roman Gushchin
2019-11-22 16:28 ` Christian Borntraeger
2019-11-24 0:39 ` Roman Gushchin
2019-11-25 8:00 ` Christian Borntraeger
2019-11-25 18:07 ` Roman Gushchin
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