This occured when resuming from hibernate (actually the first successfull resume on this laptop ever!).

Version-Release number of selected component (if applicable):
kernel-3.3.0-0.rc3.git7.2.fc17

[ INFO: possible circular locking dependency detected ]
3.3.0-0.rc3.git7.2.fc17.x86_64 #1 Not tainted
-------------------------------------------------------
pm-hibernate/8930 is trying to acquire lock:
 (&type->s_umount_key#19){+++++.}, at: [<ffffffff811be5a8>] thaw_super+0x28/0xd0

but task is already holding lock:
 (&fs_info->cleaner_mutex){+.+.+.}, at: [<ffffffffa01abdf1>] btrfs_freeze+0x31/0x40 [btrfs]

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&fs_info->cleaner_mutex){+.+.+.}:
       [<ffffffff810ccb91>] lock_acquire+0xa1/0x1e0
       [<ffffffff8169a316>] mutex_lock_nested+0x76/0x3a0
       [<ffffffffa01d0bf6>] btrfs_commit_super+0x26/0xd0 [btrfs]
       [<ffffffffa01d2670>] close_ctree+0x2a0/0x310 [btrfs]
       [<ffffffffa01ac039>] btrfs_put_super+0x19/0x20 [btrfs]
       [<ffffffff811bea01>] generic_shutdown_super+0x61/0xf0
       [<ffffffff811beb26>] kill_anon_super+0x16/0x30
       [<ffffffffa01afd0a>] btrfs_kill_super+0x1a/0x90 [btrfs]
       [<ffffffff811be547>] deactivate_locked_super+0x57/0x90
       [<ffffffff811be7be>] deactivate_super+0x4e/0x70
       [<ffffffff811ddcf1>] mntput_no_expire+0xb1/0x100
       [<ffffffff811dea66>] sys_umount+0x76/0x370
       [<ffffffff816a6f29>] system_call_fastpath+0x16/0x1b

-> #0 (&type->s_umount_key#19){+++++.}:
       [<ffffffff810cbdc8>] __lock_acquire+0x13d8/0x1ad0
       [<ffffffff810ccb91>] lock_acquire+0xa1/0x1e0
       [<ffffffff8169b721>] down_write+0x61/0xb0
       [<ffffffff811be5a8>] thaw_super+0x28/0xd0
       [<ffffffff811bf9d8>] thaw_supers+0xb8/0xd0
       [<ffffffff810b6482>] hibernate+0x122/0x220
       [<ffffffff810b38cc>] state_store+0x10c/0x130
       [<ffffffff8131eecf>] kobj_attr_store+0xf/0x20
       [<ffffffff812347b6>] sysfs_write_file+0xe6/0x160
       [<ffffffff811bb44f>] vfs_write+0xaf/0x190
       [<ffffffff811bb78d>] sys_write+0x4d/0x90
       [<ffffffff816a6f29>] system_call_fastpath+0x16/0x1b

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&fs_info->cleaner_mutex);
                               lock(&type->s_umount_key#19);
                               lock(&fs_info->cleaner_mutex);
  lock(&type->s_umount_key#19);

 *** DEADLOCK ***

5 locks held by pm-hibernate/8930:
 #0:  (&buffer->mutex){+.+.+.}, at: [<ffffffff81234718>] sysfs_write_file+0x48/0x160
 #1:  (s_active#109){.+.+.+}, at: [<ffffffff8123479b>] sysfs_write_file+0xcb/0x160
 #2:  (pm_mutex){+.+.+.}, at: [<ffffffff810b638c>] hibernate+0x2c/0x220
 #3:  (&fs_info->transaction_kthread_mutex){+.+.+.}, at: [<ffffffffa01abde3>] btrfs_freeze+0x23/0x40 [btrfs]
 #4:  (&fs_info->cleaner_mutex){+.+.+.}, at: [<ffffffffa01abdf1>] btrfs_freeze+0x31/0x40 [btrfs]

stack backtrace:
Pid: 8930, comm: pm-hibernate Not tainted 3.3.0-0.rc3.git7.2.fc17.x86_64 #1
Call Trace:
 [<ffffffff81692a4e>] print_circular_bug+0x1fb/0x20c
 [<ffffffff810cbdc8>] __lock_acquire+0x13d8/0x1ad0
 [<ffffffff81020ee3>] ? native_sched_clock+0x13/0x80
 [<ffffffff810ccb91>] lock_acquire+0xa1/0x1e0
 [<ffffffff811be5a8>] ? thaw_super+0x28/0xd0
 [<ffffffff8169b721>] down_write+0x61/0xb0
 [<ffffffff811be5a8>] ? thaw_super+0x28/0xd0
 [<ffffffff811be5a8>] thaw_super+0x28/0xd0
 [<ffffffff811bf9d8>] thaw_supers+0xb8/0xd0
 [<ffffffff810b6482>] hibernate+0x122/0x220
 [<ffffffff810b38cc>] state_store+0x10c/0x130
 [<ffffffff8131eecf>] kobj_attr_store+0xf/0x20
 [<ffffffff812347b6>] sysfs_write_file+0xe6/0x160
 [<ffffffff811bb44f>] vfs_write+0xaf/0x190
 [<ffffffff811bb78d>] sys_write+0x4d/0x90
 [<ffffffff816a6f29>] system_call_fastpath+0x16/0x1b