Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933088Ab2EWA05 (ORCPT ); Tue, 22 May 2012 20:26:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51852 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752274Ab2EWA0w (ORCPT ); Tue, 22 May 2012 20:26:52 -0400 Date: Tue, 22 May 2012 20:26:45 -0400 From: Dave Jones To: Linux Kernel Cc: Alan Cox , Greg Kroah-Hartman Subject: 3.4+ tty lockdep trace Message-ID: <20120523002645.GA3490@redhat.com> Mail-Followup-To: Dave Jones , Linux Kernel , Alan Cox , Greg Kroah-Hartman 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 Content-Length: 2546 Lines: 53 >From v3.4-4413-gfb09baf [ 43.374948] ============================================= [ 43.374991] [ INFO: possible recursive locking detected ] [ 43.375035] 3.4.0+ #24 Not tainted [ 43.375065] --------------------------------------------- [ 43.375108] sshd/639 is trying to acquire lock: [ 43.375157] (&tty->legacy_mutex){+.+.+.}, at: [] tty_lock+0x37/0x80 [ 43.375216] [ 43.375216] but task is already holding lock: [ 43.375268] (&tty->legacy_mutex){+.+.+.}, at: [] tty_lock+0x37/0x80 [ 43.375327] [ 43.375327] other info that might help us debug this: [ 43.375378] Possible unsafe locking scenario: [ 43.375378] [ 43.375425] CPU0 [ 43.375447] ---- [ 43.375471] lock(&tty->legacy_mutex); [ 43.375504] lock(&tty->legacy_mutex); [ 43.375536] [ 43.375536] *** DEADLOCK *** [ 43.375536] [ 43.375583] May be due to missing lock nesting notation [ 43.375583] [ 43.375637] 2 locks held by sshd/639: [ 43.375675] #0: (tty_mutex){+.+.+.}, at: [] tty_release+0x1c3/0x5d0 [ 43.375740] #1: (&tty->legacy_mutex){+.+.+.}, at: [] tty_lock+0x37/0x80 [ 43.375802] [ 43.375802] stack backtrace: [ 43.375841] Pid: 639, comm: sshd Not tainted 3.4.0+ #24 [ 43.375882] Call Trace: [ 43.377572] [] __lock_acquire+0x1584/0x1aa0 [ 43.379286] [] lock_acquire+0x92/0x1f0 [ 43.380995] [] ? tty_lock+0x37/0x80 [ 43.382700] [] mutex_lock_nested+0x71/0x3b0 [ 43.384403] [] ? tty_lock+0x37/0x80 [ 43.386094] [] ? get_parent_ip+0x11/0x50 [ 43.387794] [] ? tty_lock+0x37/0x80 [ 43.389480] [] ? sub_preempt_count+0x6d/0xd0 [ 43.391176] [] ? tty_release+0x1c3/0x5d0 [ 43.393003] [] tty_lock+0x37/0x80 [ 43.394867] [] tty_lock_pair+0x23/0x5c [ 43.396671] [] tty_release+0x1ce/0x5d0 [ 43.398462] [] fput+0x12c/0x300 [ 43.400292] [] filp_close+0x69/0xa0 [ 43.402084] [] sys_close+0xad/0x1a0 [ 43.403871] [] system_call_fastpath+0x16/0x1b -- 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/