Re: [Bug #13068] Lockdep warning in inotify_dev_queue_event

From: Sachin Sant
Date: Wed Apr 22 2009 - 05:51:13 EST

Rafael J. Wysocki wrote:
This message has been generated automatically as a part of a report
of recent regressions.

The following bug entry is on the current list of known regressions
from 2.6.29. Please verify if it still should be listed and let me know
(either way).


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 2.6.30-rc3 as well.

=================================
[ INFO: inconsistent lock state ]
2.6.30-rc3 #1
---------------------------------
inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
inotify02/31550 [HC0[0]:SC0[0]:HE1:SE1] takes:
(&inode->inotify_mutex){+.+.?.}, at: [<c0000000001668ec>] .inotify_inode_queue_event+0x6c/0x160
{IN-RECLAIM_FS-W} state was registered at:
[<c00000000009bb1c>] .lock_acquire+0x108/0x154
[<c0000000005a8be4>] .mutex_lock_nested+0x88/0x460
[<c000000000166b04>] .inotify_inode_is_dead+0x38/0xc8
[<c000000000142708>] .dentry_iput+0xa0/0x128
[<c000000000142904>] .d_kill+0x5c/0xa0
[<c000000000142c4c>] .__shrink_dcache_sb+0x304/0x3d0
[<c000000000142e5c>] .shrink_dcache_memory+0x144/0x244
[<c0000000000f580c>] .shrink_slab+0x15c/0x228
[<c0000000000f60f8>] .kswapd+0x4c4/0x67c
[<c000000000088ba4>] .kthread+0x80/0xcc
[<c00000000002c194>] .kernel_thread+0x54/0x70
irq event stamp: 2267
hardirqs last enabled at (2267): [<c000000000120490>] .kmem_cache_alloc+0xec/0x1b4
hardirqs last disabled at (2266): [<c000000000120418>] .kmem_cache_alloc+0x74/0x1b4
softirqs last enabled at (1654): [<c00000000002be8c>] .call_do_softirq+0x14/0x24
softirqs last disabled at (1639): [<c00000000002be8c>] .call_do_softirq+0x14/0x24

other info that might help us debug this:
4 locks held by inotify02/31550:
#0: (&type->i_mutex_dir_key#4){+.+.+.}, at: [<c00000000013d41c>] .do_filp_open+0x1a4/0x964
#1: (&inode->inotify_mutex){+.+.?.}, at: [<c0000000001668ec>] .inotify_inode_queue_event+0x6c/0x160
#2: (&ih->mutex){+.+...}, at: [<c000000000166920>] .inotify_inode_queue_event+0xa0/0x160
#3: (&dev->ev_mutex){+.+...}, at: [<c00000000016822c>] .inotify_dev_queue_event+0x50/0x1cc

stack backtrace:
Call Trace:
[c00000001816b4b0] [c000000000011a54] .show_stack+0x6c/0x16c (unreliable)
[c00000001816b560] [c000000000098544] .print_usage_bug+0x1c0/0x1f4
[c00000001816b620] [c0000000000988f8] .mark_lock+0x380/0x6e4
[c00000001816b6d0] [c000000000098cd0] .mark_held_locks+0x74/0xc0
[c00000001816b770] [c000000000098de0] .lockdep_trace_alloc+0xc4/0xf4
[c00000001816b7f0] [c000000000122090] .__kmalloc+0x100/0x274
[c00000001816b8a0] [c000000000168140] .kernel_event+0xb8/0x154
[c00000001816b940] [c0000000001682fc] .inotify_dev_queue_event+0x120/0x1cc
[c00000001816b9f0] [c000000000166970] .inotify_inode_queue_event+0xf0/0x160
[c00000001816bac0] [c000000000139acc] .vfs_create+0x170/0x1dc
[c00000001816bb60] [c00000000013d4d4] .do_filp_open+0x25c/0x964
[c00000001816bd10] [c00000000012b37c] .do_sys_open+0x80/0x140
[c00000001816bdc0] [c00000000012b258] .SyS_creat+0x18/0x2c
[c00000001816be30] [c000000000008554] syscall_exit+0x0/0x40

Let me know if i could provide any other information.

Thanks
-Sachin

--

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

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