Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753124Ab0AJSey (ORCPT ); Sun, 10 Jan 2010 13:34:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752025Ab0AJSey (ORCPT ); Sun, 10 Jan 2010 13:34:54 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:57277 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751264Ab0AJSex convert rfc822-to-8bit (ORCPT ); Sun, 10 Jan 2010 13:34:53 -0500 From: "Rafael J. Wysocki" To: "Eric W. Biederman" Subject: Re: 2.6.33-rc3 -- INFO: possible recursive locking -- (s_active){++++.+}, at: [] sysfs_hash_and_remove+0x3d/0x4f Date: Sun, 10 Jan 2010 19:35:31 +0100 User-Agent: KMail/1.12.3 (Linux/2.6.33-rc3-rjw; KDE/4.3.3; x86_64; ; ) Cc: =?utf-8?q?Am=C3=A9rico_Wang?= , Miles Lane , LKML , "Greg Kroah-Hartman" , Jesse Barnes , Len Brown , Pavel Machek References: <2375c9f91001100058w4bac1cf9s183fc37eafbfde75@mail.gmail.com> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Message-Id: <201001101935.31882.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4642 Lines: 94 On Sunday 10 January 2010, Eric W. Biederman wrote: > Américo Wang writes: > > > On Sun, Jan 10, 2010 at 4:47 PM, Américo Wang wrote: > >> > >> On Wed, Jan 06, 2010 at 07:54:59AM -0500, Miles Lane wrote: > >> >[ 6967.926563] ACPI: Preparing to enter system sleep state S3 > >> >[ 6967.956156] Disabling non-boot CPUs ... > >> >[ 6967.970401] > >> >[ 6967.970408] ============================================= > >> >[ 6967.970419] [ INFO: possible recursive locking detected ] > >> >[ 6967.970431] 2.6.33-rc2-git6 #27 > >> >[ 6967.970439] --------------------------------------------- > >> >[ 6967.970450] pm-suspend/22147 is trying to acquire lock: > >> >[ 6967.970460] (s_active){++++.+}, at: [] > >> >sysfs_hash_and_remove+0x3d/0x4f > >> >[ 6967.970493] > >> >[ 6967.970497] but task is already holding lock: > >> >[ 6967.970506] (s_active){++++.+}, at: [] > >> >sysfs_get_active_two+0x16/0x36 > >> >[ 6967.970531] > >> >[ 6967.970535] other info that might help us debug this: > >> >[ 6967.970547] 6 locks held by pm-suspend/22147: > >> >[ 6967.970556] #0: (&buffer->mutex){+.+.+.}, at: [] > >> >sysfs_write_file+0x25/0xeb > >> >[ 6967.970584] #1: (s_active){++++.+}, at: [] > >> >sysfs_get_active_two+0x16/0x36 > >> >[ 6967.970612] #2: (s_active){++++.+}, at: [] > >> >sysfs_get_active_two+0x21/0x36 > >> >[ 6967.970639] #3: (pm_mutex){+.+.+.}, at: [] enter_state+0x26/0x114 > >> >[ 6967.970668] #4: (cpu_add_remove_lock){+.+.+.}, at: [] > >> >cpu_maps_update_begin+0xf/0x11 > >> >[ 6967.970697] #5: (cpu_hotplug.lock){+.+.+.}, at: [] > >> >cpu_hotplug_begin+0x1d/0x40 > >> >[ 6967.970724] > >> >[ 6967.970728] stack backtrace: > >> >[ 6967.970740] Pid: 22147, comm: pm-suspend Not tainted 2.6.33-rc2-git6 #27 > >> >[ 6967.970751] Call Trace: > >> >[ 6967.970771] [] ? printk+0xf/0x18 > >> >[ 6967.970791] [] __lock_acquire+0x817/0xb6d > >> >[ 6967.970812] [] ? mark_held_locks+0x43/0x5b > >> >[ 6967.970831] [] ? debug_check_no_locks_freed+0xfd/0x107 > >> >[ 6967.970851] [] ? trace_hardirqs_on_caller+0x108/0x130 > >> >[ 6967.970871] [] lock_acquire+0x5c/0x73 > >> >[ 6967.970890] [] ? sysfs_hash_and_remove+0x3d/0x4f > >> >[ 6967.970910] [] sysfs_addrm_finish+0x9a/0xfe > >> >[ 6967.970929] [] ? sysfs_hash_and_remove+0x3d/0x4f > >> >[ 6967.970953] [] sysfs_hash_and_remove+0x3d/0x4f > >> >[ 6967.970974] [] sysfs_remove_group+0x52/0x81 > >> >[ 6967.970993] [] mc_cpu_callback+0x73/0x9a > >> >[ 6967.971014] [] notifier_call_chain+0x51/0x78 > >> >[ 6967.971034] [] __raw_notifier_call_chain+0xe/0x10 > >> >[ 6967.971054] [] _cpu_down+0x7a/0x235 > >> >[ 6967.971074] [] disable_nonboot_cpus+0x58/0xe0 > >> >[ 6967.971093] [] suspend_devices_and_enter+0xb9/0x173 > >> >[ 6967.971094] [] enter_state+0xc8/0x114 > >> >[ 6967.971094] [] state_store+0x93/0xa7 > >> >[ 6967.971094] [] ? state_store+0x0/0xa7 > >> >[ 6967.971094] [] kobj_attr_store+0x16/0x22 > >> >[ 6967.971094] [] sysfs_write_file+0xc0/0xeb > >> >[ 6967.971094] [] ? sysfs_write_file+0x0/0xeb > >> >[ 6967.971094] [] vfs_write+0x80/0xdf > >> >[ 6967.971094] [] sys_write+0x3b/0x5d > >> >[ 6967.971094] [] sysenter_do_call+0x12/0x36 > >> >[ 6967.973262] CPU 1 is now offline > >> >[ 6967.973271] lockdep: fixing up alternatives. > >> > >> Hmmm, does reverting commit 846f99749ab68b help? > >> > > > > Of course it will help, but the problem is not that. That patch helps > > us to detect such a problem... I am still investigating. :-/ > > This looks like this is triggered by a write to a sysfs file, > so the solution is probably to call schedule_work so the > suspend can happen outside the context of sysfs. > > The typical scenario that triggers this is: > - A lock is held while removing a sysfs attribute. > - The same lock is grabbed inside the sysfs attribute. > > I think we do that with the cpu_hotplug.lock > > In this case it looks like this might be a reach around scenario where > we try and remove the sysfs attribute that triggered the suspend. We don't do that. Rafael -- 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/