Created attachment 25634 [details] Entire dmesg output I get a lockdep warning at boot time, after "PM: Starting manual resume from disk" (it was a clean boot, not resuming). The system does boot normally though. Here's the warning: ------------------------------------------------------------ [ 12.095635] PM: Starting manual resume from disk [ 12.095855] [ 12.095856] ======================================================= [ 12.096006] [ INFO: possible circular locking dependency detected ] [ 12.096006] 2.6.33.1-lap #1 [ 12.096006] ------------------------------------------------------- [ 12.096006] resume/1035 is trying to acquire lock: [ 12.096006] (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8111561c>] __blkdev_get+0x6c/0x377 [ 12.096006] [ 12.096006] but task is already holding lock: [ 12.096006] (pm_mutex/1){+.+...}, at: [<ffffffff8107ca54>] software_resume+0x2e/0x2ec [ 12.096006] [ 12.096006] which lock already depends on the new lock. [ 12.096006] [ 12.096006] [ 12.096006] the existing dependency chain (in reverse order) is: [ 12.096006] [ 12.096006] -> #2 (pm_mutex/1){+.+...}: [ 12.096006] [<ffffffff8106f947>] __lock_acquire+0x127d/0x1607 [ 12.096006] [<ffffffff8106fd9d>] lock_acquire+0xcc/0xe9 [ 12.096006] [<ffffffff81432a01>] mutex_lock_nested+0x5e/0x2b1 [ 12.096006] [<ffffffff8107ca54>] software_resume+0x2e/0x2ec [ 12.096006] [<ffffffff8107cda8>] resume_store+0x96/0xa7 [ 12.096006] [<ffffffff8123586f>] kobj_attr_store+0x17/0x19 [ 12.096006] [<ffffffff81141270>] sysfs_write_file+0x108/0x144 [ 12.096006] [<ffffffff810edd09>] vfs_write+0xb2/0x153 [ 12.096006] [<ffffffff810ede6d>] sys_write+0x4a/0x71 [ 12.096006] [<ffffffff81002b5b>] system_call_fastpath+0x16/0x1b [ 12.096006] [ 12.096006] -> #1 (s_active){++++.+}: [ 12.096006] [<ffffffff8106f947>] __lock_acquire+0x127d/0x1607 [ 12.096006] [<ffffffff8106fd9d>] lock_acquire+0xcc/0xe9 [ 12.096006] [<ffffffff81141df5>] sysfs_deactivate+0x8b/0xc8 [ 12.096006] [<ffffffff81142761>] sysfs_addrm_finish+0x36/0x5f [ 12.096006] [<ffffffff8114092a>] sysfs_hash_and_remove+0x53/0x6a [ 12.096006] [<ffffffff81142c0b>] sysfs_remove_link+0x21/0x23 [ 12.096006] [<ffffffff8111497b>] bd_release_from_disk+0xb7/0x133 [ 12.096006] [<ffffffff8138129f>] close_dev+0x2c/0x45 [ 12.096006] [<ffffffff813812e4>] dm_put_device+0x2c/0x68 [ 12.096006] [<ffffffff81386ece>] crypt_dtr+0x95/0xa2 [ 12.096006] [<ffffffff813817b1>] dm_table_destroy+0x6c/0xee [ 12.096006] [<ffffffff8137f193>] dm_put+0xed/0x1ce [ 12.096006] [<ffffffff81384160>] dev_remove+0xb9/0xcd [ 12.096006] [<ffffffff813847de>] ctl_ioctl+0x1cf/0x227 [ 12.096006] [<ffffffff81384849>] dm_ctl_ioctl+0x13/0x17 [ 12.096006] [<ffffffff810fac33>] vfs_ioctl+0x32/0xa6 [ 12.096006] [<ffffffff810fb1c5>] do_vfs_ioctl+0x495/0x4db [ 12.096006] [<ffffffff810fb252>] sys_ioctl+0x47/0x6a [ 12.096006] [<ffffffff81002b5b>] system_call_fastpath+0x16/0x1b [ 12.096006] [ 12.096006] -> #0 (&bdev->bd_mutex){+.+.+.}: [ 12.096006] [<ffffffff8106f5f7>] __lock_acquire+0xf2d/0x1607 [ 12.096006] [<ffffffff8106fd9d>] lock_acquire+0xcc/0xe9 [ 12.096006] [<ffffffff81432a01>] mutex_lock_nested+0x5e/0x2b1 [ 12.096006] [<ffffffff8111561c>] __blkdev_get+0x6c/0x377 [ 12.096006] [<ffffffff81115937>] blkdev_get+0x10/0x12 [ 12.096006] [<ffffffff81115a8c>] open_by_devnum+0x2e/0x3f [ 12.096006] [<ffffffff8107f23e>] swsusp_check+0x22/0x168 [ 12.096006] [<ffffffff8107cb10>] software_resume+0xea/0x2ec [ 12.096006] [<ffffffff8107cda8>] resume_store+0x96/0xa7 [ 12.096006] [<ffffffff8123586f>] kobj_attr_store+0x17/0x19 [ 12.096006] [<ffffffff81141270>] sysfs_write_file+0x108/0x144 [ 12.096006] [<ffffffff810edd09>] vfs_write+0xb2/0x153 [ 12.096006] [<ffffffff810ede6d>] sys_write+0x4a/0x71 [ 12.096006] [<ffffffff81002b5b>] system_call_fastpath+0x16/0x1b [ 12.096006] [ 12.096006] other info that might help us debug this: [ 12.096006] [ 12.096006] 4 locks held by resume/1035: [ 12.096006] #0: (&buffer->mutex){+.+.+.}, at: [<ffffffff811411a4>] sysfs_write_file+0x3c/0x144 [ 12.096006] #1: (s_active){++++.+}, at: [<ffffffff81142a2c>] sysfs_get_active_two+0x24/0x48 [ 12.096006] #2: (s_active){++++.+}, at: [<ffffffff81142a39>] sysfs_get_active_two+0x31/0x48 [ 12.096006] #3: (pm_mutex/1){+.+...}, at: [<ffffffff8107ca54>] software_resume+0x2e/0x2ec [ 12.096006] [ 12.096006] stack backtrace: [ 12.096006] Pid: 1035, comm: resume Tainted: G W 2.6.33.1-lap #1 [ 12.096006] Call Trace: [ 12.096006] [<ffffffff8106d789>] print_circular_bug+0xae/0xbd [ 12.096006] [<ffffffff8106f5f7>] __lock_acquire+0xf2d/0x1607 [ 12.096006] [<ffffffff8106fa96>] ? __lock_acquire+0x13cc/0x1607 [ 12.096006] [<ffffffff8106fd9d>] lock_acquire+0xcc/0xe9 [ 12.096006] [<ffffffff8111561c>] ? __blkdev_get+0x6c/0x377 [ 12.096006] [<ffffffff8106d0e6>] ? trace_hardirqs_on+0xd/0xf [ 12.096006] [<ffffffff81432a01>] mutex_lock_nested+0x5e/0x2b1 [ 12.096006] [<ffffffff8111561c>] ? __blkdev_get+0x6c/0x377 [ 12.096006] [<ffffffff8122a548>] ? exact_match+0x0/0xf [ 12.096006] [<ffffffff8111561c>] __blkdev_get+0x6c/0x377 [ 12.096006] [<ffffffff81115937>] blkdev_get+0x10/0x12 [ 12.096006] [<ffffffff81115a8c>] open_by_devnum+0x2e/0x3f [ 12.096006] [<ffffffff8107f23e>] swsusp_check+0x22/0x168 [ 12.096006] [<ffffffff8107cb10>] software_resume+0xea/0x2ec [ 12.096006] [<ffffffff8107cda8>] resume_store+0x96/0xa7 [ 12.096006] [<ffffffff8123586f>] kobj_attr_store+0x17/0x19 [ 12.096006] [<ffffffff81141270>] sysfs_write_file+0x108/0x144 [ 12.096006] [<ffffffff810edd09>] vfs_write+0xb2/0x153 [ 12.096006] [<ffffffff8106d0b5>] ? trace_hardirqs_on_caller+0x10c/0x130 [ 12.096006] [<ffffffff810ede6d>] sys_write+0x4a/0x71 [ 12.096006] [<ffffffff81002b5b>] system_call_fastpath+0x16/0x1b ------------------------------------------------------------ Entire dmesg attached.
This warning triggers as a result of recent sysfs changes.
Still happens on 2.6.33.2.
bugzilla-daemon@bugzilla.kernel.org writes: > https://bugzilla.kernel.org/show_bug.cgi?id=15603 > > > Sami Liedes <sliedes@cc.hut.fi> changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > Kernel Version|2.6.33.1 |2.6.33.1, 2.6.33.2 > > > > > --- Comment #2 from Sami Liedes <sliedes@cc.hut.fi> 2010-04-07 22:29:34 --- > Still happens on 2.6.33.2. Lockdep warns about possible locking problems. Unfortunately the initial version of this lockdep warning had a high false positive rate. In the latest versions of 2.6.34-rcX the deeper changes needed to remove those false positives have been made. If you are interested in seeing the warning go away I suggest you try that. If a problem persists in 2.6.34-rcX it is almost certainly a real locking problem. No changes are planned for 2.6.33.x as this is believed to be a false positive, and can easily be avoided by simply turning off lockdep. Eric
Yes, we're not going to fix this in 2.6.33.x, so closing.