From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756029Ab2AQWHV (ORCPT ); Tue, 17 Jan 2012 17:07:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:9561 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755728Ab2AQWHU (ORCPT ); Tue, 17 Jan 2012 17:07:20 -0500 Date: Tue, 17 Jan 2012 17:07:15 -0500 From: Vivek Goyal To: Tejun Heo Cc: linux kernel mailing list , Jens Axboe Subject: Re: Kernel crash in icq_free_icq_rcu Message-ID: <20120117220715.GB23527@redhat.com> References: <20120117201823.GD19223@redhat.com> <20120117214834.GD26207@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120117214834.GD26207@google.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 17, 2012 at 01:48:34PM -0800, Tejun Heo wrote: > On Tue, Jan 17, 2012 at 03:18:23PM -0500, Vivek Goyal wrote: > > Hi Tejun, > > > > With latest linus kernel, I see following crash. I was running some > > scripts which create cgroups and launch fio jobs in those groups. In > > a separate window I wrote a script to change the IO scheduler on the > > device in a loop while IO was happening on the device. After few > > seconds I see following. So far I tried it twice and reproduced it > > both the times in first few seconds. > > Does the following patch make any difference? Nope. Still can reproduce the issue. Thanks Vivek > > diff --git a/block/elevator.c b/block/elevator.c > index 91e18f8..b5a94ed 100644 > --- a/block/elevator.c > +++ b/block/elevator.c > @@ -105,6 +105,7 @@ int elv_rq_merge_ok(struct request *rq, struct bio *bio) > if (bio_integrity(bio) != blk_integrity_rq(rq)) > return 0; > > + return 0; > if (!elv_iosched_allow_merge(rq, bio)) > return 0; >