From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754686Ab2LST1t (ORCPT ); Wed, 19 Dec 2012 14:27:49 -0500 Received: from mail-pa0-f47.google.com ([209.85.220.47]:64083 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753653Ab2LST1q (ORCPT ); Wed, 19 Dec 2012 14:27:46 -0500 Date: Wed, 19 Dec 2012 11:27:40 -0800 From: Tejun Heo To: Fengguang Wu Cc: Sasha Levin , LKML Subject: [PATCH] workqueue: fix find_worker_executing_work() brekage from hashtable conversion Message-ID: <20121219192740.GT1844@htj.dyndns.org> References: <20121219095241.GA27310@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121219095241.GA27310@localhost> 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 >>From 023f27d3d6fcc9048754d879fe5e7d63402a5b16 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 19 Dec 2012 11:24:06 -0800 42f8570f43 ("workqueue: use new hashtable implementation") incorrectly made busy workers hashed by the pointer value of worker instead of work. This broke find_worker_executing_work() which in turn broke a lot of fundamental operations of workqueue - non-reentrancy and flushing among others. The flush malfunction triggered warning in disk event code in Fengguang's automated test. write_dev_root_ (3265) used greatest stack depth: 2704 bytes left ------------[ cut here ]------------ WARNING: at /c/kernel-tests/src/stable/block/genhd.c:1574 disk_clear_events+0x\ cf/0x108() Hardware name: Bochs Modules linked in: Pid: 3328, comm: ata_id Not tainted 3.7.0-01930-gbff6343 #1167 Call Trace: [] warn_slowpath_common+0x83/0x9c [] warn_slowpath_null+0x1a/0x1c [] disk_clear_events+0xcf/0x108 [] check_disk_change+0x27/0x59 [] cdrom_open+0x49/0x68b [] idecd_open+0x88/0xb7 [] __blkdev_get+0x102/0x3ec [] blkdev_get+0x18f/0x30f [] blkdev_open+0x75/0x80 [] do_dentry_open+0x1ea/0x295 [] finish_open+0x35/0x41 [] do_last+0x878/0xa25 [] path_openat+0xc6/0x333 [] do_filp_open+0x38/0x86 [] do_sys_open+0x6c/0xf9 [] sys_open+0x21/0x23 [] system_call_fastpath+0x16/0x1b Signed-off-by: Tejun Heo Reported-by: Fengguang Wu Cc: Sasha Levin --- Sorry that I didn't spot this earlier. Fix applied to wq/for-3.9. Thanks a lot Fengguang. You're awesome! kernel/workqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index d24a411..7967f34 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2172,7 +2172,7 @@ __acquires(&gcwq->lock) /* claim and dequeue */ debug_work_deactivate(work); - hash_add(gcwq->busy_hash, &worker->hentry, (unsigned long)worker); + hash_add(gcwq->busy_hash, &worker->hentry, (unsigned long)work); worker->current_work = work; worker->current_func = work->func; worker->current_cwq = cwq; -- 1.8.0.2