From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756323Ab2HQODJ (ORCPT ); Fri, 17 Aug 2012 10:03:09 -0400 Received: from mga11.intel.com ([192.55.52.93]:47679 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756080Ab2HQOCs (ORCPT ); Fri, 17 Aug 2012 10:02:48 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.77,785,1336374000"; d="scan'208";a="203536870" Date: Fri, 17 Aug 2012 22:02:40 +0800 From: Fengguang Wu To: "Paul E. McKenney" Cc: Thomas Gleixner , Steven Rostedt , linux-kernel@vger.kernel.org Subject: Re: lockdep warning on rt_mutex_lock() Message-ID: <20120817140240.GB539@localhost> References: <20120817100635.GA30765@localhost> <20120817134328.GB2872@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120817134328.GB2872@linux.vnet.ibm.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 Fri, Aug 17, 2012 at 06:43:28AM -0700, Paul E. McKenney wrote: > On Fri, Aug 17, 2012 at 06:06:35PM +0800, Fengguang Wu wrote: > > Greetings, > > > > FYI, a lockdep warning: > > Certainly looks problematic! > > Any hint as to what version of the kernel produced this splat? > (Yes, lazy of me to ask, I know, but I am not seeing it in my testing.) It happens on both 3.5.0 and 3.6-rc1. Will bisect (try older kernels) help? Bisect is handy for me :) Sorry the back trace in the original email only happens in _one_ test box. That makes it hard to reproduce.. The more common test boxes see these traces (with different config). I'll send full config/dmesg for the first one in another email. [ 24.647556] init: Temporary process spawn error: No such file or directory [ 24.806072] ------------[ cut here ]------------ [ 24.807042] WARNING: at /c/kernel-tests/src/linux/kernel/lockdep.c:3493 check_flags+0x113/0x2a7() [ 24.807042] Hardware name: Bochs [ 24.807042] Pid: 8, comm: rcu_kthread Not tainted 3.6.0-rc1-00011-gf8cdda8 #2 [ 24.807042] Call Trace: [ 24.807042] [] ? up+0x50/0x5c [ 24.807042] [] warn_slowpath_common+0xb3/0xe1 [ 24.807042] [] warn_slowpath_null+0x23/0x2c [ 24.807042] [] check_flags+0x113/0x2a7 [ 24.807042] [] lock_is_held+0x4b/0xe4 [ 24.807042] [] __might_sleep+0x4e/0x277 [ 24.807042] [] rt_mutex_lock+0x23/0x54 [ 24.807042] [] rcu_boost+0xeb/0x140 [ 24.807042] [] ? _raw_spin_unlock_irqrestore+0x78/0xeb [ 24.807042] [] ? spin_unlock_irqrestore+0x10/0x19 [ 24.807042] [] ? finish_wait+0x8f/0x9f [ 24.807042] [] rcu_kthread+0xf2/0x1f0 [ 24.807042] [] ? abort_exclusive_wait+0xb7/0xb7 [ 24.807042] [] ? __rcu_process_callbacks+0x1b4/0x1b4 [ 24.807042] [] kthread+0x95/0xa4 [ 24.807042] [] kernel_thread_helper+0x4/0x10 [ 24.807042] [] ? retint_restore_args+0x13/0x13 [ 24.807042] [] ? freezing+0x2c/0x2c [ 24.807042] [] ? gs_change+0x13/0x13 [ 22.951027] [sched_delayed] sched: RT throttling activated [ 34.752102] ------------[ cut here ]------------ [ 34.753023] WARNING: at /c/kernel-tests/src/tip/kernel/lockdep.c:3493 check_flags+0xc1/0x1d0() [ 34.753023] Pid: 6, comm: rcu_kthread Not tainted 3.5.0-03701-g899852a #1 [ 34.753023] Call Trace: [ 34.753023] [] ? check_flags+0xc1/0x1d0 [ 34.753023] [] warn_slowpath_common+0x66/0x90 [ 34.753023] [] warn_slowpath_null+0x15/0x20 [ 34.753023] [] check_flags+0xc1/0x1d0 [ 34.753023] [] lock_acquire+0x63/0xe0 [ 34.753023] [] ? update_curr_rt+0xd6/0x190 [ 34.753023] [] _raw_spin_lock+0x3b/0x50 [ 34.753023] [] ? rt_mutex_slowlock+0x38/0x150 [ 34.753023] [] rt_mutex_slowlock+0x38/0x150 [ 34.753023] [] ? __raw_spin_lock_init+0x38/0x70 [ 34.753023] [] rt_mutex_lock+0x28/0x30 [ 34.753023] [] rcu_boost+0x76/0xf0 [ 34.753023] [] rcu_kthread+0xa5/0x140 [ 34.753023] [] ? abort_exclusive_wait+0xa0/0xa0 [ 34.753023] [] ? __rcu_process_callbacks+0x100/0x100 [ 34.753023] [] kthread+0x8d/0xa0 [ 34.753023] [] kernel_thread_helper+0x4/0x10 [ 34.753023] [] ? retint_restore_args+0x13/0x13 [ 34.753023] [] ? kthread_flush_work_fn+0x10/0x10 [ 34.753023] [] ? gs_change+0x13/0x13 [ 11.635806] HugeTLB registered 4 MB page size, pre-allocated 0 pages [ 12.105729] ------------[ cut here ]------------ [ 12.105729] WARNING: at /c/kernel-tests/src/i386/kernel/lockdep.c:3493 check_flags+0xaa/0x190() [ 12.105729] Hardware name: Bochs [ 12.105729] Pid: 6, comm: rcu_kthread Not tainted 3.5.0-rc5+ #30 [ 12.105729] Call Trace: [ 12.105729] [] warn_slowpath_common+0x7a/0xa0 [ 12.105729] [] ? check_flags+0xaa/0x190 [ 12.105729] [] ? check_flags+0xaa/0x190 [ 12.105729] [] warn_slowpath_null+0x1d/0x20 [ 12.105729] [] check_flags+0xaa/0x190 [ 12.105729] [] lock_acquire+0x3c/0xb0 [ 12.105729] [] ? sched_clock+0x8/0x10 [ 12.105729] [] ? sched_clock_local.constprop.2+0x15/0x150 [ 12.105729] [] _raw_spin_lock+0x40/0x70 [ 12.105729] [] ? rt_mutex_slowlock+0x26/0x130 [ 12.105729] [] rt_mutex_slowlock+0x26/0x130 [ 12.105729] [] ? debug_check_no_locks_freed+0x127/0x160 [ 12.105729] [] ? put_lock_stats.isra.19+0xd/0x30 [ 12.105729] [] rt_mutex_lock+0x19/0x20 [ 12.105729] [] rcu_kthread+0x10c/0x1c0 [ 12.105729] [] ? preempt_schedule+0x2f/0x50 [ 12.105729] [] ? complete+0x49/0x60 [ 12.105729] [] ? __rcu_process_callbacks+0x110/0x110 [ 12.105729] [] kthread+0x67/0x70 [ 12.105729] [] ? kthread_flush_work_fn+0x10/0x10 [ 12.105729] [] kernel_thread_helper+0x6/0xd Thanks, Fengguang