Re: 2.6.29-rc3: BUG: NMI Watchdog detected LOCKUP

[Ingo Molnar]

* Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

> > [ 3344.972984] Call Trace:
> > [ 3344.972984]  [<ffffffff8118d26a>] __make_request+0x3e/0x412
> > [ 3344.972984]  [<ffffffff8118bf77>] generic_make_request+0x279/0x2c3
> > [ 3344.972984]  [<ffffffff8119f189>] ? radix_tree_tag_set+0x6b/0xce
> > [ 3344.972984]  [<ffffffff8118c087>] submit_bio+0xc6/0xcf
> > [ 3344.972984]  [<ffffffff8107feb8>] ? unlock_page+0x22/0x26
> > [ 3344.972984]  [<ffffffff8109ebd4>] swap_writepage+0xa2/0xac
> > [ 3344.972984]  [<ffffffff8108a076>] shrink_page_list+0x3a7/0x67b
> > [ 3344.972984]  [<ffffffff810376f1>] ? finish_task_switch+0x68/0x88
> > [ 3344.972984]  [<ffffffff8101b822>] ? __cpus_empty+0x9/0xb
> > [ 3344.972984]  [<ffffffff8101ba27>] ? flush_tlb_page+0x66/0x83
> > [ 3344.972984]  [<ffffffff814908b3>] ? thread_return+0x3d/0xc6
> > [ 3344.972984]  [<ffffffff8108a98d>] shrink_list+0x29d/0x59f
> > [ 3344.972984]  [<ffffffff81086c4f>] ? get_dirty_limits+0x22/0x24a
> > [ 3344.972984]  [<ffffffff8108af10>] shrink_zone+0x281/0x32b
> > [ 3344.972984]  [<ffffffff8119ff8e>] ? __up_read+0x92/0x9c
> > [ 3344.972984]  [<ffffffff8108b100>] ? shrink_slab+0x146/0x158
> > [ 3344.972984]  [<ffffffff8108c022>] try_to_free_pages+0x23d/0x38f
> > [ 3344.972984]  [<ffffffff81089185>] ? isolate_pages_global+0x0/0x219
> > [ 3344.972984]  [<ffffffff81085cc9>] __alloc_pages_internal+0x292/0x43d
> > [ 3344.972984]  [<ffffffff810a6963>] alloc_pages_current+0xb9/0xc2
> > [ 3344.972984]  [<ffffffff810aa658>] alloc_slab_page+0x19/0x69
> > [ 3344.972984]  [<ffffffff810aa6f1>] new_slab+0x49/0x1cc
> > [ 3344.972984]  [<ffffffff8119f8b1>] ? rb_insert_color+0xbd/0xe6
> > [ 3344.972984]  [<ffffffff810aaad3>] __slab_alloc+0x1f3/0x36c
> > [ 3344.972984]  [<ffffffff81389fe8>] ? __alloc_skb+0x42/0x130
> > [ 3344.972984]  [<ffffffff81389fe8>] ? __alloc_skb+0x42/0x130
> > [ 3344.972984]  [<ffffffff810aaf7c>] kmem_cache_alloc_node+0x69/0xa2
> > [ 3344.972984]  [<ffffffff81389fe8>] __alloc_skb+0x42/0x130
> > [ 3344.972984]  [<ffffffff81385bd3>] sock_alloc_send_skb+0xa1/0x200
> > [ 3344.972984]  [<ffffffff8116700a>] ? security_socket_getpeersec_dgram+0x11/0x3
> > [ 3344.972984]  [<ffffffff81409250>] unix_stream_sendmsg+0x138/0x2b5
> > [ 3344.972984]  [<ffffffff8138276b>] __sock_sendmsg+0x59/0x62
> > [ 3344.972984]  [<ffffffff8138285c>] sock_aio_write+0xe8/0xf8
> > [ 3344.972984]  [<ffffffff810af9a2>] do_sync_write+0xe7/0x12d
> > [ 3344.972984]  [<ffffffff8104d980>] ? autoremove_wake_function+0x0/0x38
> > [ 3344.972984]  [<ffffffff8116d9da>] ? selinux_file_permission+0xbd/0xc6
> > [ 3344.972984]  [<ffffffff811669d0>] ? security_file_permission+0x11/0x13
> > [ 3344.972984]  [<ffffffff810b029a>] vfs_write+0xbe/0x105
> > [ 3344.972984]  [<ffffffff810b03a5>] sys_write+0x47/0x6f
> > [ 3344.972984]  [<ffffffff8102bba8>] sysenter_dispatch+0x7/0x27
> > [ 3344.972984] Code: 01 00 00 f0 66 0f c1 17 38 f2 74 06 f3 90 8a 17 eb f6 c9 c
> > [ 3344.972984] BUG: NMI Watchdog detected LOCKUP<4>---[ end trace 820f38a7b2441-
> > [ 3344.972984]  on CPU0, ip ffffffff81491f6c, registers:
> 
> And then the block layer died.  Looks like it was trying to take the
> queue lock.  Probably against the recently-offlined device.
> 
> I'd say that either someone forgot to release the lock on an error
> path.  Or the structure was freed, but the kernel still tries to use it.

Should run with CONFIG_PROVE_LOCKING=y for more precise forensics about
precisely who did that and when.

Or if this was with lockdep enabled already, some other modes of failure
should be considered too. (such as memory corruption)

	Ingo
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