From: Tejun Heo <tj@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH] slub: make sysfs file removal asynchronous
Date: Tue, 20 Jun 2017 18:00:11 -0400 [thread overview]
Message-ID: <20170620220011.GJ21326@htj.duckdns.org> (raw)
In-Reply-To: <20170620145814.9eb1b74feaf908c39e9c0de2@linux-foundation.org>
On Tue, Jun 20, 2017 at 02:58:14PM -0700, Andrew Morton wrote:
> On Tue, 20 Jun 2017 16:45:12 -0400 Tejun Heo <tj@kernel.org> wrote:
>
> > bf5eb3de3847 ("slub: separate out sysfs_slab_release() from
> > sysfs_slab_remove()") made slub sysfs file removals synchronous to
> > kmem_cache shutdown. Unfortunately, this created a possible ABBA
> > deadlock between slab_mutex and sysfs draining mechanism triggering
> > the following lockdep warning.
> >
> > ...
> >
> > Signed-off-by: Tejun Heo <tj@kernel.org>
> > Reported-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > Fixes: bf5eb3de3847 ("slub: separate out sysfs_slab_release() from sysfs_slab_remove()")
>
> Do you think we should add cc:stable [4.11+]?
I think we'd risk more by backporting it through -stable than keeping
the bug there. The bug is very difficult to hit. Writing to a slub
sysfs file has to race against kmem_cache destruction and AFAICS all
slub sysfs files are for debugging.
Thanks.
--
tejun
next prev parent reply other threads:[~2017-06-20 22:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-16 12:55 [LOCKDEP BUG] from slub: separate out sysfs_slab_release() from sysfs_slab_remove() Steven Rostedt
2017-06-19 20:35 ` Tejun Heo
2017-06-19 21:27 ` Steven Rostedt
2017-06-20 20:45 ` [PATCH] slub: make sysfs file removal asynchronous Tejun Heo
2017-06-20 21:58 ` Andrew Morton
2017-06-20 22:00 ` Tejun Heo [this message]
2017-06-20 22:22 ` Steven Rostedt
2017-06-20 22:48 ` Tejun Heo
2017-06-28 14:47 ` Christoph Lameter
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