[PATCH] xfs: remove xfs_log_ticket_zone on rmmod

[Alexey Dobriyan]

>>>> Pid: 20926, comm: cat Not tainted 2.6.25-git5 #1
>>>> RIP: 0010:[<ffffffff80357aac>]  [<ffffffff80357aac>] strnlen+0x15/0x1f
>>>> RSP: 0018:ffff810274981cc8  EFLAGS: 00010297
>>>> RAX: ffffffffa00b7551 RBX: ffff810274981d38 RCX: ffffffff80603719
>>>> RDX: ffff810274981d68 RSI: fffffffffffffffe RDI: ffffffffa00b7551
>>>> RBP: ffff810274981cc8 R08: 00000000ffffffff R09: 00000000000000c8
>>>> R10: 0000000000000050 R11: 0000000000000246 R12: ffff8102364600cc
>>>> R13: ffffffffa00b7551 R14: 0000000000000011 R15: 0000000000000010
>>>> FS:  00007f956375d6f0(0000) GS:ffff81027f808980(0000) 
>>>> knlGS:00000000f7f7f6c0
>>>> CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
>>>> CR2: ffffffffa00b7551 CR3: 00000002734d5000 CR4: 00000000000006e0
>>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>>> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
>>>> Process cat (pid: 20926, threadinfo ffff810274980000, task 
>>>> ffff81026d18ce20)
>>>> Stack:  ffff810274981d28 ffffffff80358d5a ffff810274981d28 
>>>> 0000000000000f34
>>>>  ffff8102364600cc ffff810236461000 ffffffff80603719 ffff81024ac14f00
>>>>  ffff81024ac14f00 0000000000000004 0000000000000000 0000000000000000
>>>> Call Trace:
>>>>  [<ffffffff80358d5a>] vsnprintf+0x31b/0x592
>>>>  [<ffffffff802a78eb>] seq_printf+0x7e/0xa7
>>>>  [<ffffffff8024c6fe>] ? debug_mutex_free_waiter+0x46/0x4a
>>>>  [<ffffffff8053aaa2>] ? __down_read+0x17/0x92
>>>>  [<ffffffff80539c25>] ? __mutex_lock_slowpath+0x1d8/0x1e5
>>>>  [<ffffffff802886c2>] ? count_partial+0x45/0x4d
>>>>  [<ffffffff80289a6d>] s_show+0x7e/0xcb
>>>>  [<ffffffff802a7dd9>] seq_read+0x10b/0x298
>>>>  [<ffffffff802c7dbb>] proc_reg_read+0x7b/0x95
>>>>  [<ffffffff8028ec0b>] vfs_read+0xab/0x154
>>>>  [<ffffffff8028f015>] sys_read+0x47/0x6f
>>>>  [<ffffffff8020c182>] tracesys+0xd5/0xda
>>>>
>>>>
>>>> Code: 48 8d 44 11 ff 40 38 30 74 0a 48 ff c8 48 39 d0 73 f3 31 c0 c9 c3 
>>>> 55 48 89 f8 48 89 e5 eb 03 48 ff c0 48 ff ce 48 83 fe ff 74 05 <80> 38 
>>>> 00 75 ef c9 48 29 f8 c3 55 31 c0 48 89 e5 eb 13 41 38 c8 RIP  
>>>> [<ffffffff80357aac>] strnlen+0x15/0x1f
>>>>  RSP <ffff810274981cc8>
>>>> CR2: ffffffffa00b7551
>>>>
>>>>
>>>> ---
>>>>
>>>>         
>>> My initial thoughts are :
>>>
>>> Fault address is  0xffffffffa00b7551 which is in module mapping space on 
>>> x86_64
>>>
>>> strnlen() is OK
>>>
>>> Some module created a kmem_cache (with kmem_cache_create()).
>>> slub or slab kept a pointer to the cache name in their internal
>>> structures.
>>> Module was unloaded but forgot to destroy kmem cache before unloading.
>>>
>>> Fault happens while doing "cat /proc/slabinfo", when trying to 
>>> dereference cache name since module was unloaded and its memory unmapped.
>>>
>>> Next step is to find which module was unloaded ...
>>>     
>>
>> The last one was reiserfs, apparently ;).

Which doesn't mean anything ;-)

>>   
> Yes but reiserfs correctly destroys its cache at unload time.
>
> Must be something else...


[PATCH] xfs: remove xfs_log_ticket_zone on rmmod

Bug introduces in commit eb01c9cd87c7a9998c2edf209721ea069e3e3652
aka "[XFS] Remove the xlog_ticket allocator"

Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
---

 fs/xfs/xfs_vfsops.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/xfs/xfs_vfsops.c
+++ b/fs/xfs/xfs_vfsops.c
@@ -186,6 +186,7 @@ xfs_cleanup(void)
 	kmem_zone_destroy(xfs_efi_zone);
 	kmem_zone_destroy(xfs_ifork_zone);
 	kmem_zone_destroy(xfs_ili_zone);
+	kmem_zone_destroy(xfs_log_ticket_zone);
 }
 
 /*

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