[dm-devel] might_sleep warning in multipath_dtr

Martin George marting at netapp.com
Wed May 7 19:36:08 UTC 2008


On Wednesday 07 May 2008 04:37:16 Christof Schmitt wrote:
> A test with multipathing and periodic path failures (2.6.25 on s390x)
> hit this problem:
>
>    <3>BUG: sleeping function called from invalid context at
> /home/autobuild/BUILD/linux-2.6.25-20080430/kernel/workqueue.c:396
> <4>in_atomic():1, irqs_disabled():0
>     <4>CPU: 1 Not tainted 2.6.25-28.x.20080430-s390xdefault #1
>     <4>Process pdflush (pid: 19981, task: 0000000008914538, ksp:
> 000000001418fba8) <4>0000000000000000 000000001418fac0 0000000000000002
> 0000000000000000 <4>       000000001418fb60 000000001418fad8
> 000000001418fad8 000000000010563c <4>       0000000000000000
> 000000001418fba8 0000000000000000 0000000000000000 <4>      
> 000000001418fac0 000000000000000c 000000001418fac0 000000001418fb30 <4>    
>   0000000000464aa0 000000000010563c 000000001418fac0 000000001418fb10
> <4>Call Trace:
>     <4>([<00000000001055c2>] show_trace+0x12e/0x13c)
>     <4> [<0000000000105696>] show_stack+0xc6/0xf8
>     <4> [<0000000000105e58>] dump_stack+0xb0/0xc0
>     <4> [<0000000000129092>] __might_sleep+0x106/0x128
>     <4> [<000000000014e344>] flush_workqueue+0x44/0x9c
>     <4> [<000003e00008f79c>] multipath_dtr+0x38/0x50 [dm_multipath]
>     <4> [<000003e000077e4a>] dm_table_put+0xae/0x134 [dm_mod]
>     <4> [<000003e000076020>] dm_any_congested+0x50/0x88 [dm_mod]
>     <4> [<00000000001e09c0>] sync_sb_inodes+0xa4/0x334
>     <4> [<00000000001e0f9e>] writeback_inodes+0xfa/0x130
>     <4> [<0000000000189e04>] wb_kupdate+0xd0/0x170
>     <4> [<000000000018a65a>] pdflush+0x14a/0x22c
>     <4> [<0000000000152bec>] kthread+0x68/0xa0
>     <4> [<000000000010a0be>] kernel_thread_starter+0x6/0xc
>     <4> [<000000000010a0b8>] kernel_thread_starter+0x0/0xc
>
> After the bug message, the CPU is waiting in _raw_spin_relax:
>
> ================================================================
> TASK HAS CPU (1): 0x8914538 (pdflush):
>  LOWCORE INFO:
>   -psw      : 0x0704100180000000 0x00000000002aa8f6
>   -function : _raw_spin_relax+94
>   -prefix   : 0x1fb04000
>   -cpu timer: 0x7fffd1ed 0xa3fc6a40
>   -clock cmp: 0x00c25518 0x4f9f8839
>   -general registers:
>      000000000000000000 0x0000000000000004
>      0x000000000067b728 0x0000000000000002
>      0x0000000000455632 0x0000000000485ec0
>      000000000000000000 0x000000001af244b8
>      0x000000001e6daf60 0x000000000021bfd4
>      0x0000000001046ca0 0x000000001418f8a8
>      0x00000000006abdc0 0x000000000046f218
>      0x000000000045561e 0x000000001418f8a8
>   -access registers:
>      0000000000 0000000000 0000000000 0000000000
>      0000000000 0000000000 0000000000 0000000000
>      0000000000 0000000000 0000000000 0000000000
>      0000000000 0000000000 0000000000 0000000000
>   -control registers:
>      0x0000000014354e12 0x0000000000676007
>      0x0000000000011200 000000000000000000
>      0x0000000000004e0d 0x0000000000011200
>      0x0000000011000000 0x0000000000676007
>      000000000000000000 000000000000000000
>      000000000000000000 000000000000000000
>      000000000000000000 0x00000000154641c7
>      0x00000000db000000 000000000000000000
>   -floating point registers:
>      000000000000000000 000000000000000000
>      000000000000000000 000000000000000000
>      000000000000000000 000000000000000000
>      000000000000000000 000000000000000000
>      000000000000000000 000000000000000000
>      000000000000000000 000000000000000000
>      000000000000000000 000000000000000000
>      000000000000000000 000000000000000000
>
>  STACK:
>  0 ifind+66 [0x1d299e]
>  1 ilookup5_nowait+90 [0x1d2af2]
>  2 sysfs_addrm_start+98 [0x21c506]
>  3 sysfs_hash_and_remove+66 [0x21ac82]
>  4 sysfs_remove_link+44 [0x21d8b4]
>  5 del_symlink+60 [0x1edeb8]
>  6 bd_release_from_disk+218 [0x1edfd6]
>  7 close_dev+74 [0x3e000077202]
>  8 dm_put_device+88 [0x3e000077280]
>  9 free_priority_group+138 [0x3e00008f672]
> 10 free_multipath+100 [0x3e00008f708]
> 11 multipath_dtr+66 [0x3e00008f7a6]
> 12 dm_table_put+174 [0x3e000077e4a]
> 13 dm_any_congested+80 [0x3e000076020]
> 14 sync_sb_inodes+164 [0x1e09c0]
> 15 writeback_inodes+250 [0x1e0f9e]
> 16 wb_kupdate+208 [0x189e04]
> 17 pdflush+330 [0x18a65a]
> 18 kthread+104 [0x152bec]
> 19 kernel_thread_starter+6 [0x10a0be]
>
> I don't know, if this exact situation is reproducible, but we have a
> memory dump that should have some more data.
>
> Any ideas how to debug this problem?
>
> Christof
>
> --
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