kernel 2.6.21-1.3116.fc7 possible circular locking dependency

[Alexandru Ciobanu]

Upon booting 2.6.21 kernel on my HP500 notebook I get a kind of weid 
info message which I've pasted below.
I'm using a custom 2.6.21-1.3116 kernel [I've included a small patch in 
drivers/input/serio/i8042.c to get my touchpad going (BZ #230595)] and 
reiserfs for filesystem. I'm not experiencing any problems with my 
system and I definitely have no ideea what this error(?) is about.
Any ideas?

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.21-1.3116ics.fc7 #1
-------------------------------------------------------
chgrp/1221 is trying to acquire lock:
  (&REISERFS_SB(s)->xattr_dir_sem){..--}, at: [<e00e6c6c>] 
reiserfs_chown_xattrs+0x4e/0x106 [reiserfs]

but task is already holding lock:
  (&inode->i_mutex){--..}, at: [<c0614c6a>] mutex_lock+0x21/0x24

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:
-> #1 (&inode->i_mutex){--..}:
        [<c044299f>] __lock_acquire+0xa19/0xba4
        [<c0442f1c>] lock_acquire+0x56/0x6f
        [<c0614ad2>] __mutex_lock_slowpath+0xf7/0x26e
        [<c0614c6a>] mutex_lock+0x21/0x24
        [<e00e5f54>] get_xa_root+0x4a/0x10b [reiserfs]
        [<e00e604c>] open_xa_dir+0x19/0xde [reiserfs]
        [<e00e716e>] reiserfs_delete_xattrs+0x58/0x160 [reiserfs]
        [<e00cc07b>] reiserfs_delete_inode+0x5d/0xe8 [reiserfs]
        [<c048f6ca>] generic_delete_inode+0xa6/0x110
        [<c048f746>] generic_drop_inode+0x12/0x130
        [<c048ed32>] iput+0x63/0x66
        [<c0487305>] do_unlinkat+0xb6/0x123
        [<c0487382>] sys_unlink+0x10/0x12
        [<c0405078>] syscall_call+0x7/0xb
        [<ffffffff>] 0xffffffff

-> #0 (&REISERFS_SB(s)->xattr_dir_sem){..--}:
        [<c0442883>] __lock_acquire+0x8fd/0xba4
        [<c0442f1c>] lock_acquire+0x56/0x6f
        [<c043b7fc>] down_read+0x3f/0x51
        [<e00e6c6c>] reiserfs_chown_xattrs+0x4e/0x106 [reiserfs]
        [<e00cbedb>] reiserfs_setattr+0x115/0x258 [reiserfs]
        [<c04901a3>] notify_change+0x127/0x2c8
        [<c047d232>] chown_common+0x93/0xa6
        [<c047d3d6>] sys_chown+0x34/0x46
        [<c0405078>] syscall_call+0x7/0xb
        [<ffffffff>] 0xffffffff

other info that might help us debug this:

1 lock held by chgrp/1221:
  #0:  (&inode->i_mutex){--..}, at: [<c0614c6a>] mutex_lock+0x21/0x24

stack backtrace:
  [<c04061e9>] show_trace_log_lvl+0x1a/0x2f
  [<c04067ad>] show_trace+0x12/0x14
  [<c0406831>] dump_stack+0x16/0x18
  [<c0441096>] print_circular_bug_tail+0x5f/0x68
  [<c0442883>] __lock_acquire+0x8fd/0xba4
  [<c0442f1c>] lock_acquire+0x56/0x6f
  [<c043b7fc>] down_read+0x3f/0x51
  [<e00e6c6c>] reiserfs_chown_xattrs+0x4e/0x106 [reiserfs]
  [<e00cbedb>] reiserfs_setattr+0x115/0x258 [reiserfs]
  [<c04901a3>] notify_change+0x127/0x2c8
  [<c047d232>] chown_common+0x93/0xa6
  [<c047d3d6>] sys_chown+0x34/0x46
  [<c0405078>] syscall_call+0x7/0xb
  =======================