Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751921Ab2K1GR1 (ORCPT ); Wed, 28 Nov 2012 01:17:27 -0500 Received: from cantor2.suse.de ([195.135.220.15]:54429 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751281Ab2K1GRZ (ORCPT ); Wed, 28 Nov 2012 01:17:25 -0500 Message-ID: <1354083438.4506.3.camel@marge.simpson.net> Subject: [patch] workqueue: exit rescuer_thread() as TASK_RUNNING From: Mike Galbraith To: LKML Cc: Tejun Heo Date: Wed, 28 Nov 2012 07:17:18 +0100 Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2541 Lines: 59 A rescue thread exiting TASK_INTERRUPTIBLE can lead to a task scheduling off, never to be seen again. In the case where this occurred, an exiting thread hit reiserfs homebrew conditional resched while holding a mutex, bringing the box to it's knees. PID: 18105 TASK: ffff8807fd412180 CPU: 5 COMMAND: "kdmflush" #0 [ffff8808157e7670] schedule at ffffffff8143f489 #1 [ffff8808157e77b8] reiserfs_get_block at ffffffffa038ab2d [reiserfs] #2 [ffff8808157e79a8] __block_write_begin at ffffffff8117fb14 #3 [ffff8808157e7a98] reiserfs_write_begin at ffffffffa0388695 [reiserfs] #4 [ffff8808157e7ad8] generic_perform_write at ffffffff810ee9e2 #5 [ffff8808157e7b58] generic_file_buffered_write at ffffffff810eeb41 #6 [ffff8808157e7ba8] __generic_file_aio_write at ffffffff810f1a3a #7 [ffff8808157e7c58] generic_file_aio_write at ffffffff810f1c88 #8 [ffff8808157e7cc8] do_sync_write at ffffffff8114f850 #9 [ffff8808157e7dd8] do_acct_process at ffffffff810a268f #10 [ffff8808157e7e78] acct_process at ffffffff810a27ba #11 [ffff8808157e7e98] do_exit at ffffffff8105e29a #12 [ffff8808157e7ee8] kthread at ffffffff8107afee #13 [ffff8808157e7f48] kernel_thread_helper at ffffffff8144a5c4 [exception RIP: kernel_thread_helper] RIP: ffffffff8144a5c0 RSP: ffff8808157e7f58 RFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8107af60 RDI: ffff8803ee491d18 RBP: 0000000000000000 R8: 0000000000000000 R9: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 Signed-off-by: Mike Galbraith Cc: stable@vger.kernel.org kernel/workqueue.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 042d221..ac25db1 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2407,8 +2407,10 @@ static int rescuer_thread(void *__wq) repeat: set_current_state(TASK_INTERRUPTIBLE); - if (kthread_should_stop()) + if (kthread_should_stop()) { + __set_current_state(TASK_RUNNING); return 0; + } /* * See whether any cpu is asking for help. Unbounded -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/