From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757452AbYELSdl (ORCPT ); Mon, 12 May 2008 14:33:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751588AbYELSdd (ORCPT ); Mon, 12 May 2008 14:33:33 -0400 Received: from hu-out-0506.google.com ([72.14.214.233]:1733 "EHLO hu-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753133AbYELSdc (ORCPT ); Mon, 12 May 2008 14:33:32 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:mime-version:content-type:content-disposition:user-agent; b=DpiK77IWsGRXy9UGA7QP6teUdUHQ3BnO7Zn/gMDM/zwMPsC7EgRJHijUKuJ4m6MC8/Dn6u1PtCrR5UzSIBcCY5/ppO6gqyTZIy5KDEqi/LwfwYyryJwXTkrviMqbDiNIizq7x6HqscQ4P5rNtfN631ltM+kWTzoQ6X2CUAbJGhs= Date: Mon, 12 May 2008 20:32:59 +0200 From: Marcin Slusarz To: LKML Cc: Alan Cox , Alexander Viro Subject: [vfs/tty] possible circular locking dependency detected Message-ID: <20080512183235.GB6031@joi> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org May 11 08:52:08 [kernel] [ 21.052750] Clocksource tsc unstable (delta = -109466779 ns) May 11 09:42:27 [kernel] [ 1104.496819] rarian-sk-get-c[5630]: segfault at 0 ip 7f478556caf0 sp 7fff8e3fe338 error 4 in libc-2.6.1.so[7f47854f9000+136000] May 11 10:59:48 [kernel] [ 2494.165792] May 11 10:59:48 [kernel] [ 2494.165794] ======================================================= May 11 10:59:48 [kernel] [ 2494.165801] [ INFO: possible circular locking dependency detected ] May 11 10:59:48 [kernel] [ 2494.165805] 2.6.26-rc1-00007-g91b3a7a #217 May 11 10:59:48 [kernel] [ 2494.165807] ------------------------------------------------------- May 11 10:59:48 [kernel] [ 2494.165809] less/7053 is trying to acquire lock: May 11 10:59:48 [kernel] [ 2494.165812] (tasklist_lock){..??}, at: [] is_current_pgrp_orphaned+0x15/0x50 May 11 10:59:48 [kernel] [ 2494.165821] May 11 10:59:48 [kernel] [ 2494.165822] but task is already holding lock: May 11 10:59:48 [kernel] [ 2494.165824] (&tty->ctrl_lock){....}, at: [] tty_check_change+0x61/0x110 May 11 10:59:48 [kernel] [ 2494.165831] May 11 10:59:48 [kernel] [ 2494.165832] which lock already depends on the new lock. May 11 10:59:48 [kernel] [ 2494.165833] May 11 10:59:48 [kernel] [ 2494.165835] May 11 10:59:48 [kernel] [ 2494.165836] the existing dependency chain (in reverse order) is: May 11 10:59:48 [kernel] [ 2494.165838] May 11 10:59:48 [kernel] [ 2494.165839] -> #2 (&tty->ctrl_lock){....}: May 11 10:59:48 [kernel] [ 2494.165843] [] __lock_acquire+0xf86/0x1080 May 11 10:59:48 [kernel] [ 2494.165851] [] lock_acquire+0x92/0xc0 May 11 10:59:48 [kernel] [ 2494.165858] [] _spin_lock_irqsave+0x40/0x60 May 11 10:59:48 [kernel] [ 2494.165866] [] __proc_set_tty+0x35/0xe0 May 11 10:59:48 [kernel] [ 2494.165873] [] tty_ioctl+0xbf4/0xfe0 May 11 10:59:48 [kernel] [ 2494.165880] [] vfs_ioctl+0x31/0x90 May 11 10:59:48 [kernel] [ 2494.165888] [] do_vfs_ioctl+0x73/0x2d0 May 11 10:59:48 [kernel] [ 2494.165895] [] sys_ioctl+0x4a/0x80 May 11 10:59:48 [kernel] [ 2494.165902] [] system_call_after_swapgs+0x7b/0x80 May 11 10:59:48 [kernel] [ 2494.165910] [] 0xffffffffffffffff May 11 10:59:48 [kernel] [ 2494.165924] May 11 10:59:48 [kernel] [ 2494.165925] -> #1 (&sighand->siglock){++..}: May 11 10:59:48 [kernel] [ 2494.165929] [] __lock_acquire+0xf86/0x1080 May 11 10:59:48 [kernel] [ 2494.165936] [] lock_acquire+0x92/0xc0 May 11 10:59:48 [kernel] [ 2494.165943] [] _spin_lock+0x2f/0x40 May 11 10:59:48 [kernel] [ 2494.165951] [] copy_process+0x973/0x1210 May 11 10:59:48 [kernel] [ 2494.165959] [] do_fork+0x82/0x2f0 May 11 10:59:48 [kernel] [ 2494.165967] [] kernel_thread+0x81/0xde May 11 10:59:48 [kernel] [ 2494.165974] [] child_rip+0xa/0x12 May 11 10:59:48 [kernel] [ 2494.165981] [] 0xffffffffffffffff May 11 10:59:48 [kernel] [ 2494.166038] May 11 10:59:48 [kernel] [ 2494.166039] -> #0 (tasklist_lock){..??}: May 11 10:59:48 [kernel] [ 2494.166043] [] __lock_acquire+0xd9b/0x1080 May 11 10:59:48 [kernel] [ 2494.166050] [] lock_acquire+0x92/0xc0 May 11 10:59:48 [kernel] [ 2494.166057] [] _read_lock+0x32/0x50 May 11 10:59:48 [kernel] [ 2494.166063] [] is_current_pgrp_orphaned+0x15/0x50 May 11 10:59:48 [kernel] [ 2494.166071] [] tty_check_change+0xb0/0x110 May 11 10:59:48 [kernel] [ 2494.166078] [] set_termios+0x1f/0x4c0 May 11 10:59:48 [kernel] [ 2494.166085] [] tty_mode_ioctl+0x279/0x3e0 May 11 10:59:48 [kernel] [ 2494.166092] [] n_tty_ioctl+0x3d/0x260 May 11 10:59:48 [kernel] [ 2494.166100] [] tty_ioctl+0x154/0xfe0 May 11 10:59:48 [kernel] [ 2494.166107] [] vfs_ioctl+0x31/0x90 May 11 10:59:48 [kernel] [ 2494.166114] [] do_vfs_ioctl+0x73/0x2d0 May 11 10:59:48 [kernel] [ 2494.166121] [] sys_ioctl+0x4a/0x80 May 11 10:59:48 [kernel] [ 2494.166128] [] system_call_after_swapgs+0x7b/0x80 May 11 10:59:48 [kernel] [ 2494.166135] [] 0xffffffffffffffff May 11 10:59:48 [kernel] [ 2494.166142] May 11 10:59:48 [kernel] [ 2494.166143] other info that might help us debug this: May 11 10:59:48 [kernel] [ 2494.166144] May 11 10:59:48 [kernel] [ 2494.166146] 1 lock held by less/7053: May 11 10:59:48 [kernel] [ 2494.166148] #0: (&tty->ctrl_lock){....}, at: [] tty_check_change+0x61/0x110 May 11 10:59:48 [kernel] [ 2494.166155] May 11 10:59:48 [kernel] [ 2494.166156] stack backtrace: May 11 10:59:48 [kernel] [ 2494.166159] Pid: 7053, comm: less Not tainted 2.6.26-rc1-00007-g91b3a7a #217 May 11 10:59:48 [kernel] [ 2494.166161] May 11 10:59:48 [kernel] [ 2494.166162] Call Trace: May 11 10:59:48 [kernel] [ 2494.166168] [] print_circular_bug_tail+0x83/0x90 May 11 10:59:48 [kernel] [ 2494.166172] [] ? print_circular_bug_entry+0x49/0x60 May 11 10:59:48 [kernel] [ 2494.166178] [] __lock_acquire+0xd9b/0x1080 May 11 10:59:48 [kernel] [ 2494.166184] [] ? is_current_pgrp_orphaned+0x15/0x50 May 11 10:59:48 [kernel] [ 2494.166189] [] lock_acquire+0x92/0xc0 May 11 10:59:48 [kernel] [ 2494.166206] [] tty_check_change+0xb0/0x110 May 11 10:59:48 [kernel] [ 2494.166211] [] set_termios+0x1f/0x4c0 May 11 10:59:48 [kernel] [ 2494.166216] [] ? tty_ldisc_try+0x23/0x60 May 11 10:59:48 [kernel] [ 2494.166220] [] ? tty_ldisc_try+0x44/0x60 May 11 10:59:48 [kernel] [ 2494.166224] [] ? _spin_unlock_irqrestore+0x65/0x80 May 11 10:59:48 [kernel] [ 2494.166230] [] tty_mode_ioctl+0x279/0x3e0 May 11 10:59:48 [kernel] [ 2494.166234] [] ? tty_ldisc_try+0x44/0x60 May 11 10:59:48 [kernel] [ 2494.166239] [] n_tty_ioctl+0x3d/0x260 May 11 10:59:48 [kernel] [ 2494.166244] [] tty_ioctl+0x154/0xfe0 May 11 10:59:48 [kernel] [ 2494.166249] [] ? __lock_acquire+0x39a/0x1080 May 11 10:59:48 [kernel] [ 2494.166256] [] ? __lock_acquire+0x39a/0x1080 May 11 10:59:48 [kernel] [ 2494.166263] [] ? __lock_acquire+0x39a/0x1080 May 11 10:59:48 [kernel] [ 2494.166269] [] vfs_ioctl+0x31/0x90 May 11 10:59:48 [kernel] [ 2494.166274] [] do_vfs_ioctl+0x73/0x2d0 May 11 10:59:48 [kernel] [ 2494.166280] [] sys_ioctl+0x4a/0x80 May 11 10:59:48 [kernel] [ 2494.166286] [] system_call_after_swapgs+0x7b/0x80 May 11 10:59:48 [kernel] [ 2494.166292] It was on 2.6.26-rc1 + some patches (afa26be86b65a7183ceac29bdf1f51d6fc6932f0) I think it had something to do with a hang of my yakuake (KDE terminal emulator) session. But I'm not sure (I noticed this warning much later)