Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755232AbYKKCKt (ORCPT ); Mon, 10 Nov 2008 21:10:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754096AbYKKCKi (ORCPT ); Mon, 10 Nov 2008 21:10:38 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:56108 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754412AbYKKCKg (ORCPT ); Mon, 10 Nov 2008 21:10:36 -0500 From: KOSAKI Motohiro To: Oleg Nesterov Subject: Re: [Bug #11380] lockdep warning: cpu_add_remove_lock at:cpu_maps_update_begin+0x14/0x16 Cc: kosaki.motohiro@jp.fujitsu.com, Ingo Molnar , "Rafael J. Wysocki" , Dmitry Torokhov , Dmitry Adamushko , Max Krasnyansky , Linux Kernel Mailing List , Kernel Testers List In-Reply-To: <20081110132208.GB10294@redhat.com> References: <20081110073047.GA28578@elte.hu> <20081110132208.GB10294@redhat.com> Message-Id: <20081111105706.6174.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.42 [ja] Date: Tue, 11 Nov 2008 11:10:33 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4100 Lines: 92 > On 11/10, Ingo Molnar wrote: > > > > * Rafael J. Wysocki wrote: > > > > > This message has been generated automatically as a part of a report > > > of regressions introduced between 2.6.26 and 2.6.27. > > > > > > The following bug entry is on the current list of known regressions > > > introduced between 2.6.26 and 2.6.27. Please verify if it still should > > > be listed and let me know (either way). > > > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=11380 > > > Subject : lockdep warning: cpu_add_remove_lock at:cpu_maps_update_begin+0x14/0x16 > > > Submitter : Ingo Molnar > > > Date : 2008-08-20 6:44 (82 days old) > > > References : http://marc.info/?l=linux-kernel&m=121921480931970&w=4 > > > > had a quick look again: i believe this one still triggers, and it's > > caused by some interaction between input code and workqueue code. I > > think it started triggering when Oleg's workqueue annotation patches > > went upstream: > > > > 6af8bf3: workqueues: add comments to __create_workqueue_key() > > 8448502: workqueues: do CPU_UP_CANCELED if CPU_UP_PREPARE fails > > 8de6d30: workqueues: schedule_on_each_cpu() can use schedule_work_on() > > ef1ca23: workqueues: queue_work() can use queue_work_on() > > a67da70: workqueues: lockdep annotations for flush_work() > > 3da1c84: workqueues: make get_online_cpus() useable for work->func() > > 8616a89: workqueues: schedule_on_each_cpu: use flush_work() > > db70089: workqueues: implement flush_work() > > 1a4d9b0: workqueues: insert_work: use "list_head *" instead of "int tail" > > "make get_online_cpus() useable for work->func()" changed the locking. > destroy_workqueue() was changed to take cpu_maps_update_begin() instead > of get_online_cpus(). Other patches can't make any difference afaics. > > Currently I don't understand why lockdep complains, will try to do > more grepping later. I check original report. Is this really cpu hotplug related warnings? it seem simple ABBA lock, right? -> #4 (&dev->mutex){--..}: [] validate_chain+0x831/0xaa2 [] __lock_acquire+0x67a/0x6e0 [] lock_acquire+0x5b/0x81 [] mutex_lock_interruptible_nested+0xde/0x2f8 [] input_register_handle+0x26/0x7a dev->mutex [] kbd_connect+0x64/0x8d [] input_attach_handler+0x38/0x6b [] input_register_handler+0x74/0xc3 input_mutex [] kbd_init+0x66/0x91 [] vty_init+0xce/0xd7 [] tty_init+0x193/0x197 [] do_one_initcall+0x42/0x133 [] kernel_init+0x16e/0x1d5 [] kernel_thread_helper+0x7/0x10 [] 0xffffffff -> #3 (input_mutex){--..}: [] validate_chain+0x831/0xaa2 [] __lock_acquire+0x67a/0x6e0 [] lock_acquire+0x5b/0x81 [] mutex_lock_interruptible_nested+0xde/0x2f8 [] input_register_device+0xff/0x17f input_mutex [] acpi_button_add+0x31e/0x429 [] acpi_device_probe+0x43/0xde [] driver_probe_device+0xa5/0x120 [] __driver_attach+0x42/0x64 dev->sem [] bus_for_each_dev+0x43/0x65 [] driver_attach+0x19/0x1b [] bus_add_driver+0x9e/0x1a1 [] driver_register+0x76/0xd2 [] acpi_bus_register_driver+0x3f/0x41 [] acpi_button_init+0x32/0x51 [] do_one_initcall+0x42/0x133 [] do_async_initcalls+0x1a/0x2a [] run_workqueue+0xc3/0x193 [] worker_thread+0xbb/0xc7 [] kthread+0x40/0x66 [] kernel_thread_helper+0x7/0x10 [] 0xffffffff -- 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/