From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755034AbZIJDZs (ORCPT ); Wed, 9 Sep 2009 23:25:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755013AbZIJDZr (ORCPT ); Wed, 9 Sep 2009 23:25:47 -0400 Received: from mail-px0-f194.google.com ([209.85.216.194]:43878 "EHLO mail-px0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755009AbZIJDZq convert rfc822-to-8bit (ORCPT ); Wed, 9 Sep 2009 23:25:46 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=p8IMRs88tGTBSM/ypw2tyHHj5DoZeFP3V9f817A0+vMOGfv82ua8AOAUsH8RXEU4Rp BvagvnsdkOk72kbK9s5FuL5ag5H0Y8Pw6KlzTXgUpCYtLAh7er8FxngrV0KjN482jeW5 A9oaWoSkENKN7jC8TjlGmuDEqVnQfxi/4ntok= MIME-Version: 1.0 In-Reply-To: <6278d2220909091420g688bd11fybc33be4e472757b1@mail.gmail.com> References: <6278d2220909091420g688bd11fybc33be4e472757b1@mail.gmail.com> Date: Thu, 10 Sep 2009 11:25:49 +0800 Message-ID: Subject: Re: [2.6.31-rc9] hotplug SATA vs lockdep: false positive? From: Ming Lei To: Daniel J Blueman Cc: Linux Kernel , linux-acpi@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2009/9/10 Daniel J Blueman : > When hot-plugging my SATA DVD drive into my laptop, I see a lockdep > warning [1]. On closer inspection, both flush_workqueue() and > worker_thread() do tricks with lockdep maps. False positive? > Call Trace: >  [] print_circular_bug_tail+0xa7/0x100 >  [] __lock_acquire+0xef1/0x1240 >  [] ? add_lock_to_list+0x58/0xf0 >  [] lock_acquire+0x11e/0x170 >  [] ? flush_workqueue+0x0/0xf0 (workqueue.c:397) >  [] ? acpi_os_execute_hp_deferred+0x0/0x3e >  [] flush_workqueue+0x5c/0xf0 (workqueue.c:403) The lockdep warning is caused by calling flush_workqueue() from the work function of acpi_os_execute_hp_deferred. I don't know if it is safe to do that. >  [] ? flush_workqueue+0x0/0xf0 (workqueue.c:397) >  [] acpi_os_wait_events_complete+0x10/0x1e drivers/acpi/osl.c >  [] acpi_os_execute_hp_deferred+0x2a/0x3e >  [] worker_thread+0x248/0x3c0 (workqueue.c:292) >  [] ? worker_thread+0x1f2/0x3c0 >  [] ? autoremove_wake_function+0x0/0x40 >  [] ? worker_thread+0x0/0x3c0 >  [] kthread+0xa6/0xc0 >  [] child_rip+0xa/0x20 >  [] ? restore_args+0x0/0x30 >  [] ? kthread+0x0/0xc0 >  [] ? child_rip+0x0/0x20 > -- Lei Ming