Re: [Bug #13068] Lockdep warining in inotify_dev_queue_event

[Sachin Sant]

Rafael J. Wysocki wrote:
> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=13068
> Subject		: Lockdep warining in inotify_dev_queue_event
> Submitter	: Sachin Sant <sachinp@xxxxxxxxxx>
> Date		: 2009-04-05 12:37 (12 days old)
> References	: http://marc.info/?l=linux-kernel&m=123893439229272&w=4
>   
I can recreate this with latest kernel. Easiest way is to use the LTP mm 
tests (runltp -f mm )

=================================
[ INFO: inconsistent lock state ]
2.6.30-rc2-git4 #4
---------------------------------
inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
kswapd0/334 [HC0[0]:SC0[0]:HE1:SE1] takes:
(&inode->inotify_mutex){+.+.?.}, at: [<c000000000166cc0>] 
.inotify_inode_is_dead+0x38/0xc8
{RECLAIM_FS-ON-W} state was registered at:
 [<c000000000098d74>] .lockdep_trace_alloc+0xc4/0xf4
 [<c000000000122128>] .__kmalloc+0x100/0x274
 [<c0000000001682fc>] .kernel_event+0xb8/0x154
 [<c0000000001684b8>] .inotify_dev_queue_event+0x120/0x1cc
 [<c000000000166b2c>] .inotify_inode_queue_event+0xf0/0x160
 [<c000000000139c08>] .vfs_create+0x170/0x1dc
 [<c00000000013d5c0>] .do_filp_open+0x25c/0x964
 [<c00000000012b414>] .do_sys_open+0x80/0x140
 [<c00000000012b2f0>] .SyS_creat+0x18/0x2c
 [<c000000000008554>] syscall_exit+0x0/0x40
irq event stamp: 75815
hardirqs last  enabled at (75815): [<c0000000000cb824>] 
.__call_rcu+0x128/0x15c
hardirqs last disabled at (75814): [<c0000000000cb748>] 
.__call_rcu+0x4c/0x15c
softirqs last  enabled at (73084): [<c00000000002be8c>] 
.call_do_softirq+0x14/0x24
softirqs last disabled at (73071): [<c00000000002be8c>] 
.call_do_softirq+0x14/0x24

other info that might help us debug this:
2 locks held by kswapd0/334:
#0:  (shrinker_rwsem){++++..}, at: [<c0000000000f57c8>] 
.shrink_slab+0x5c/0x228
#1:  (&type->s_umount_key#15){++++..}, at: [<c000000000142f00>] 
.shrink_dcache_memory+0xfc/0x244

stack backtrace:
Call Trace:
[c00000004473b440] [c000000000011a54] .show_stack+0x6c/0x16c (unreliable)
[c00000004473b4f0] [c0000000000984d8] .print_usage_bug+0x1c0/0x1f4
[c00000004473b5b0] [c00000000009888c] .mark_lock+0x380/0x6e4
[c00000004473b660] [c00000000009a99c] .__lock_acquire+0x7a8/0x17b4
[c00000004473b760] [c00000000009bab0] .lock_acquire+0x108/0x154
[c00000004473b820] [c0000000005a8bac] .mutex_lock_nested+0x88/0x460
[c00000004473b920] [c000000000166cc0] .inotify_inode_is_dead+0x38/0xc8
[c00000004473b9d0] [c0000000001427f4] .dentry_iput+0xa0/0x128
[c00000004473ba60] [c0000000001429f0] .d_kill+0x5c/0xa0
[c00000004473baf0] [c000000000142d38] .__shrink_dcache_sb+0x304/0x3d0
[c00000004473bbd0] [c000000000142f48] .shrink_dcache_memory+0x144/0x244
[c00000004473bcb0] [c0000000000f58c8] .shrink_slab+0x15c/0x228
[c00000004473bd70] [c0000000000f61a4] .kswapd+0x4c0/0x678
[c00000004473bf00] [c000000000088ba4] .kthread+0x80/0xcc
[c00000004473bf90] [c00000000002c194] .kernel_thread+0x54/0x70

Thanks
-Sachin

--

---------------------------------
Sachin Sant
IBM Linux Technology Center
India Systems and Technology Labs
Bangalore, India
---------------------------------

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