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From: Shaohua Li <shaohua.li@intel.com>
To: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>,
	linux kernel mailing list <linux-kernel@vger.kernel.org>,
	Jens Axboe <axboe@kernel.dk>
Subject: Re: Kernel crash in icq_free_icq_rcu
Date: Wed, 18 Jan 2012 09:30:53 +0800	[thread overview]
Message-ID: <1326850253.22361.619.camel@sli10-conroe> (raw)
In-Reply-To: <20120118011112.GB32160@htj.dyndns.org>

On Tue, 2012-01-17 at 17:11 -0800, Tejun Heo wrote:
> On Wed, Jan 18, 2012 at 09:05:26AM +0800, Shaohua Li wrote:
> > > Vivek is seeing the problem while switching elevators.  Are you too?
> > > Or is it during normal operation?
> > same here. I had some problems when I debug my ioscheduler, but
> > eventually found even switching cfq and noop can trigger oops.
> 
> Hmmm... maybe quiescing isn't working as expected and kmem cache is
> being destroyed with live icq's.  I'll try to reproduce it.
this debug patch seems to fix for me.

diff --git a/block/blk-core.c b/block/blk-core.c
index e6c05a9..c6a8ef5 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -872,11 +872,11 @@ retry:
 	spin_unlock_irq(q->queue_lock);
 
 	/* create icq if missing */
-	if (unlikely(et->icq_cache && !icq))
+	if (unlikely(et->icq_cache && !icq && (rw_flags & REQ_ELVPRIV)))
 		icq = ioc_create_icq(q, gfp_mask);
 
 	/* rqs are guaranteed to have icq on elv_set_request() if requested */
-	if (likely(!et->icq_cache || icq))
+	if (likely(!et->icq_cache || icq || !(rw_flags & REQ_ELVPRIV)))
 		rq = blk_alloc_request(q, icq, rw_flags, gfp_mask);
 
 	if (unlikely(!rq)) {



  reply	other threads:[~2012-01-18  1:30 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-17 20:18 Kernel crash in icq_free_icq_rcu Vivek Goyal
2012-01-17 20:19 ` Jens Axboe
2012-01-17 20:40   ` Vivek Goyal
2012-01-17 20:42     ` Jens Axboe
2012-01-17 20:58       ` Vivek Goyal
2012-01-17 21:01         ` Vivek Goyal
2012-01-17 21:48 ` Tejun Heo
2012-01-17 22:07   ` Vivek Goyal
2012-01-18  1:01     ` Shaohua Li
2012-01-18  1:03       ` Tejun Heo
2012-01-18  1:05         ` Shaohua Li
2012-01-18  1:11           ` Tejun Heo
2012-01-18  1:30             ` Shaohua Li [this message]
2012-01-18  2:26               ` Shaohua Li
2012-01-18  4:23                 ` Shaohua Li
2012-01-18  6:03               ` Shaohua Li
2012-01-18 13:51                 ` Vivek Goyal
2012-01-18 14:20                   ` Vivek Goyal
2012-01-18 16:09                     ` Tejun Heo
2012-01-18 16:24                       ` Jens Axboe
2012-01-18 16:31                         ` Jens Axboe
2012-01-18 16:36                           ` Vivek Goyal
2012-01-18 17:10                             ` Tejun Heo
2012-01-18 19:07                               ` Jens Axboe
2012-01-18 19:05                             ` Jens Axboe
2012-01-18 16:55                           ` Tejun Heo
2012-01-18 16:07                 ` Tejun Heo
2012-01-19  1:41                   ` [patch]block: fix NULL icq_cache reference Shaohua Li
2012-01-19  1:43                     ` Tejun Heo
2012-01-19  8:20                     ` Jens Axboe

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