From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754359Ab0ETRBE (ORCPT ); Thu, 20 May 2010 13:01:04 -0400 Received: from eden-out.rutgers.edu ([128.6.68.11]:42153 "EHLO goshen7.rutgers.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753666Ab0ETRBB (ORCPT ); Thu, 20 May 2010 13:01:01 -0400 X-Greylist: delayed 1618 seconds by postgrey-1.27 at vger.kernel.org; Thu, 20 May 2010 13:01:01 EDT Date: Thu, 20 May 2010 12:34:00 -0400 (EDT) From: Ciprian Docan X-X-Sender: docan@er1.rutgers.edu To: linux-kernel@vger.kernel.org Subject: possible circular locking dependency detected Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I got the following in the dmesg: -------------------------------------------------------------------- [ INFO: possible circular locking dependency detected ] 2.6.33-rc8 #4 ------------------------------------------------------- fdisk/29231 is trying to acquire lock: (&type->s_umount_key#47){++++..}, at: [] get_super+0x5c/0xaf but task is already holding lock: (&bdev->bd_mutex){+.+.+.}, at: [] blkdev_ioctl+0x5c5/0x6b1 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&bdev->bd_mutex){+.+.+.}: [] __lock_acquire+0xb5d/0xd05 [] lock_acquire+0xcc/0xe9 [] __mutex_lock_common+0x4c/0x348 [] mutex_lock_nested+0x3e/0x43 [] __blkdev_put+0x34/0x16c [] blkdev_put+0x10/0x12 [] close_bdev_exclusive+0x24/0x2d [] get_sb_bdev+0xef/0x1a1 [] vfat_get_sb+0x18/0x1a [vfat] [] vfs_kern_mount+0xa9/0x168 [] do_kern_mount+0x4d/0xed [] do_mount+0x72f/0x7a6 [] sys_mount+0x88/0xc2 [] system_call_fastpath+0x16/0x1b -> #0 (&type->s_umount_key#47){++++..}: [] __lock_acquire+0xa07/0xd05 [] lock_acquire+0xcc/0xe9 [] down_read+0x51/0x84 [] get_super+0x5c/0xaf [] fsync_bdev+0x18/0x48 [] invalidate_partition+0x25/0x42 [] rescan_partitions+0x37/0x3a7 [] blkdev_ioctl+0x5d4/0x6b1 [] block_ioctl+0x37/0x3b [] vfs_ioctl+0x32/0xa6 [] do_vfs_ioctl+0x490/0x4d6 [] sys_ioctl+0x56/0x79 [] system_call_fastpath+0x16/0x1b other info that might help us debug this: 1 lock held by fdisk/29231: #0: (&bdev->bd_mutex){+.+.+.}, at: [] blkdev_ioctl+0x5c5/0x6b1 stack backtrace: Pid: 29231, comm: fdisk Not tainted 2.6.33-rc8 #4 Call Trace: [] print_circular_bug+0xa8/0xb6 [] __lock_acquire+0xa07/0xd05 [] ? sched_clock_local+0x1c/0x82 [] lock_acquire+0xcc/0xe9 [] ? get_super+0x5c/0xaf [] ? lock_release_holdtime+0x2c/0xdb [] down_read+0x51/0x84 [] ? get_super+0x5c/0xaf [] get_super+0x5c/0xaf [] fsync_bdev+0x18/0x48 [] invalidate_partition+0x25/0x42 [] ? mutex_trylock+0x12a/0x159 [] rescan_partitions+0x37/0x3a7 [] ? trace_hardirqs_on+0xd/0xf [] ? blkdev_ioctl+0x5c5/0x6b1 [] blkdev_ioctl+0x5d4/0x6b1 [] ? trace_hardirqs_on_caller+0x118/0x13c [] block_ioctl+0x37/0x3b [] vfs_ioctl+0x32/0xa6 [] do_vfs_ioctl+0x490/0x4d6 [] sys_ioctl+0x56/0x79 [] ? __wake_up+0x22/0x4d [] system_call_fastpath+0x16/0x1b ------------------------------------------------------------------------- Kernel version used: 2.6.33-rc8 #4. I do not remember the exact steps, but I was trying to format an USB stick using the fdisk. Please let me know if you need additional informations. Thank you. Regards, -- Ciprian Docan