From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932281Ab1ALRnL (ORCPT ); Wed, 12 Jan 2011 12:43:11 -0500 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:42726 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754691Ab1ALRnH (ORCPT ); Wed, 12 Jan 2011 12:43:07 -0500 Date: Wed, 12 Jan 2011 17:43:00 +0000 From: Russell King To: Linux Kernel List Subject: INFO: task rcu_kthread:6 blocked for more than 120 seconds. Message-ID: <20110112174300.GA6504@flint.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I'm seeing rcu_kthread get stuck from time to time on ARM Versatile PB (ARM926). Kernel is based upon commit 9e9bc973 (immediately prior to the merge of the OMAP tree.) ~ # ps aux|grep rcu root 6 0.0 0.0 0 0 ? S 02:31 0:01 [rcu_kthread] root 502 9.0 0.3 3740 472 ttyAMA0 S+ 02:59 0:00 grep rcu ~ # ps aux|grep rcu root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread] root 504 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu ~ # ps aux|grep rcu root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread] root 506 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu ~ # ps aux|grep rcu root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread] root 508 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu ~ # cat /proc/6/wchan rcu_kthread ~ # INFO: task rcu_kthread:6 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. rcu_kthread D c02c6684 0 6 2 0x00000000 Backtrace: [] (schedule+0x0/0x354) from [] (rcu_kthread+0x78/0xf4) [] (rcu_kthread+0x0/0xf4) from [] (kthread+0x88/0x90) [] (kthread+0x0/0x90) from [] (do_exit+0x0/0x5f8) r7:00000013 r6:c004d12c r5:c0063324 r4:c181df28 no locks held by rcu_kthread/6. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: