From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759609Ab1KWDi4 (ORCPT ); Tue, 22 Nov 2011 22:38:56 -0500 Received: from mx1.redhat.com ([209.132.183.28]:65503 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756110Ab1KWDiz (ORCPT ); Tue, 22 Nov 2011 22:38:55 -0500 Date: Tue, 22 Nov 2011 22:38:50 -0500 From: Dave Jones To: Linux Kernel Cc: Greg Kroah-Hartman , Havard Skinnemoen Subject: tty related lockdep trace during bootup on 3.2-rc2 Message-ID: <20111123033850.GA11380@redhat.com> Mail-Followup-To: Dave Jones , Linux Kernel , Greg Kroah-Hartman , Havard Skinnemoen MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 >>From Linus' current tree... related to 5dc2470c602da8851907ec18942cd876c3b4ecc1 maybe ? Dave [ 40.778011] ====================================================== [ 40.780010] [ INFO: possible circular locking dependency detected ] [ 40.780010] 3.2.0-rc2+ #8 [ 40.780010] ------------------------------------------------------- [ 40.780010] modem-manager/1141 is trying to acquire lock: [ 40.780010] (big_tty_mutex){+.+.+.}, at: [] tty_lock+0x17/0x19 [ 40.780010] [ 40.780010] but task is already holding lock: [ 40.780010] (open_mutex){+.+...}, at: [] acm_tty_close+0x41/0xc0 [cdc_acm] [ 40.780010] [ 40.780010] which lock already depends on the new lock. [ 40.780010] [ 40.780010] [ 40.780010] the existing dependency chain (in reverse order) is: [ 40.780010] [ 40.780010] -> #1 (open_mutex){+.+...}: [ 40.780010] [] lock_acquire+0x9d/0x210 [ 40.780010] [] __mutex_lock_common+0x5e/0x4f0 [ 40.780010] [] mutex_lock_nested+0x44/0x50 [ 40.780010] [] acm_tty_open+0x35/0x230 [cdc_acm] [ 40.780010] [] tty_open+0x247/0x5d0 [ 40.780010] [] chrdev_open+0x258/0x350 [ 40.780010] [] __dentry_open+0x384/0x550 [ 40.780010] [] nameidata_to_filp+0x74/0x80 [ 40.780010] [] do_last+0x26c/0x920 [ 40.780010] [] path_openat+0xd5/0x3e0 [ 40.780010] [] do_filp_open+0x42/0xa0 [ 40.780010] [] do_sys_open+0xf7/0x1d0 [ 40.780010] [] sys_open+0x20/0x30 [ 40.780010] [] system_call_fastpath+0x16/0x1b [ 40.780010] [ 40.780010] -> #0 (big_tty_mutex){+.+.+.}: [ 40.780010] [] __lock_acquire+0x16ce/0x1c40 [ 40.780010] [] lock_acquire+0x9d/0x210 [ 40.780010] [] __mutex_lock_common+0x5e/0x4f0 [ 40.780010] [] mutex_lock_nested+0x44/0x50 [ 40.780010] [] tty_lock+0x17/0x19 [ 40.780010] [] tty_port_close_start+0x17d/0x210 [ 40.780010] [] acm_tty_close+0x4f/0xc0 [cdc_acm] [ 40.780010] [] tty_release+0x167/0x5c0 [ 40.780010] [] fput+0xfe/0x2d0 [ 40.780010] [] filp_close+0x69/0x90 [ 40.780010] [] sys_close+0xc0/0x1a0 [ 40.780010] [] system_call_fastpath+0x16/0x1b [ 40.780010] [ 40.780010] other info that might help us debug this: [ 40.780010] [ 40.780010] Possible unsafe locking scenario: [ 40.780010] [ 40.780010] CPU0 CPU1 [ 40.780010] ---- ---- [ 40.780010] lock(open_mutex); [ 40.780010] lock(big_tty_mutex); [ 40.780010] lock(open_mutex); [ 40.780010] lock(big_tty_mutex); [ 40.780010] [ 40.780010] *** DEADLOCK *** [ 40.780010] [ 40.780010] 1 lock held by modem-manager/1141: [ 40.780010] #0: (open_mutex){+.+...}, at: [] acm_tty_close+0x41/0xc0 [cdc_acm] [ 40.780010] [ 40.780010] stack backtrace: [ 40.780010] Pid: 1141, comm: modem-manager Not tainted 3.2.0-rc2+ #8 [ 40.780010] Call Trace: [ 40.780010] [] print_circular_bug+0x202/0x213 [ 40.780010] [] __lock_acquire+0x16ce/0x1c40 [ 40.780010] [] ? native_sched_clock+0x22/0x70 [ 40.780010] [] ? sched_clock_local+0x25/0x90 [ 40.780010] [] lock_acquire+0x9d/0x210 [ 40.780010] [] ? tty_lock+0x17/0x19 [ 40.780010] [] ? lock_release_non_nested+0x16a/0x350 [ 40.780010] [] __mutex_lock_common+0x5e/0x4f0 [ 40.780010] [] ? tty_lock+0x17/0x19 [ 40.780010] [] ? mark_held_locks+0x86/0x150 [ 40.780010] [] ? mutex_unlock+0xe/0x10 [ 40.780010] [] ? tty_lock+0x17/0x19 [ 40.780010] [] mutex_lock_nested+0x44/0x50 [ 40.780010] [] tty_lock+0x17/0x19 [ 40.780010] [] tty_port_close_start+0x17d/0x210 [ 40.780010] [] acm_tty_close+0x4f/0xc0 [cdc_acm] [ 40.780010] [] tty_release+0x167/0x5c0 [ 40.780010] [] ? sched_clock+0x9/0x10 [ 40.780010] [] ? sched_clock_local+0x25/0x90 [ 40.780010] [] fput+0xfe/0x2d0 [ 40.780010] [] filp_close+0x69/0x90 [ 40.780010] [] sys_close+0xc0/0x1a0 [ 40.780010] [] system_call_fastpath+0x16/0x1b