On Tue, 2009-01-06 at 14:56 -0800, Andrew Morton wrote:
> I just built current mainline plus the just-sent 266 -mm patches.
>
> The machine failed to power off when hit with `halt -pfn'. dmesg output:
> [ 672.162677] INFO: task nfsd4:4324 blocked for more than 480 seconds.
> [ 672.162706] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [ 672.162725] ffff880251df1d60 0000000000000046 ffff88025e1c0580 ffff8802488013d8
> [ 672.162753] ffff880251df1d20 ffff88024c49a7a0 ffff88025e088760 ffff88024c49ab18
> [ 672.162834] 000000002807ee00 00000000ffff59ec ffff880251df1d50 0000000000000282
> [ 672.162865] Call Trace:
> [ 672.162880] [<ffffffff8052a1d8>] __mutex_lock_slowpath+0x6a/0xac
> [ 672.162895] [<ffffffff8052a0c5>] mutex_lock+0x2c/0x30
> [ 672.162908] [<ffffffff802c4747>] vfs_fsync+0x63/0xa9
> [ 672.162933] [<ffffffffa048c74c>] nfsd_sync_dir+0x10/0x12 [nfsd]
> [ 672.162960] [<ffffffffa04a5427>] nfsd4_sync_rec_dir+0x27/0x40 [nfsd]
> [ 672.162984] [<ffffffffa04a592a>] nfsd4_recdir_purge_old+0x3d/0x6a [nfsd]
> [ 672.163023] [<ffffffffa04a1745>] laundromat_main+0x62/0x225 [nfsd]
> [ 672.163049] [<ffffffffa04a16e3>] ? laundromat_main+0x0/0x225 [nfsd]
> [ 672.163064] [<ffffffff8024b4a7>] run_workqueue+0x8d/0x124
> [ 672.163076] [<ffffffff8024b5e0>] ? worker_thread+0x0/0xe5
> [ 672.163089] [<ffffffff8024b6b8>] worker_thread+0xd8/0xe5
> [ 672.163102] [<ffffffff8024e8cc>] ? autoremove_wake_function+0x0/0x36
> [ 672.163115] [<ffffffff8024b5e0>] ? worker_thread+0x0/0xe5
> [ 672.163127] [<ffffffff8024e5e0>] kthread+0x44/0x6b
> [ 672.163140] [<ffffffff8020cfba>] child_rip+0xa/0x20
> [ 672.163151] [<ffffffff8024e59c>] ? kthread+0x0/0x6b
> [ 672.163162] [<ffffffff8020cfb0>] ? child_rip+0x0/0x20
FWIW lockdep seems to warn about this...
All I have to do to trigger this is boot the machine and let it sit for
a few minutes.
[ 113.552497] =============================================
[ 113.553289] [ INFO: possible recursive locking detected ]
[ 113.553289] 2.6.28-tip #592
[ 113.553289] ---------------------------------------------
[ 113.553289] nfsd4/1914 is trying to acquire lock:
[ 113.553289] (&type->i_mutex_dir_key#4){--..}, at: [<ffffffff802e7e5e>] vfs_fsync+0x6c/0xb1
[ 113.553289]
[ 113.553289] but task is already holding lock:
[ 113.553289] (&type->i_mutex_dir_key#4){--..}, at: [<ffffffffa0190727>] nfsd4_sync_rec_dir+0x22/0x47 [nfsd]
[ 113.553289]
[ 113.553289] other info that might help us debug this:
[ 113.553289] 4 locks held by nfsd4/1914:
[ 113.553289] #0: (nfsd4){--..}, at: [<ffffffff80252303>] run_workqueue+0xb6/0x21b
[ 113.553289] #1: ((laundromat_work).work){--..}, at: [<ffffffff80252303>] run_workqueue+0xb6/0x21b
[ 113.553289] #2: (client_mutex){--..}, at: [<ffffffffa018bd05>] laundromat_main+0x33/0x24e [nfsd]
[ 113.553289] #3: (&type->i_mutex_dir_key#4){--..}, at: [<ffffffffa0190727>] nfsd4_sync_rec_dir+0x22/0x47 [nfsd]
[ 113.553289]
[ 113.553289] stack backtrace:
[ 113.553289] Pid: 1914, comm: nfsd4 Not tainted 2.6.28-tip #592
[ 113.553289] Call Trace:
[ 113.553289] [<ffffffff80266987>] __lock_acquire+0xe42/0x161a
[ 113.553289] [<ffffffff80288857>] ? __call_rcu+0x7a/0x107
[ 113.553289] [<ffffffff802671b4>] lock_acquire+0x55/0x71
[ 113.553289] [<ffffffff802e7e5e>] ? vfs_fsync+0x6c/0xb1
[ 113.553289] [<ffffffff805568d0>] mutex_lock_nested+0x4e/0x320
[ 113.553289] [<ffffffff802e7e5e>] ? vfs_fsync+0x6c/0xb1
[ 113.553289] [<ffffffff8029bde0>] ? __filemap_fdatawrite_range+0x57/0x5f
[ 113.553289] [<ffffffff802e7e5e>] vfs_fsync+0x6c/0xb1
[ 113.553289] [<ffffffffa0176f8f>] nfsd_sync_dir+0x15/0x17 [nfsd]
[ 113.553289] [<ffffffffa0190733>] nfsd4_sync_rec_dir+0x2e/0x47 [nfsd]
[ 113.553289] [<ffffffffa0190791>] nfsd4_recdir_purge_old+0x45/0x73 [nfsd]
[ 113.553289] [<ffffffffa018bd44>] laundromat_main+0x72/0x24e [nfsd]
[ 113.553289] [<ffffffff80252355>] run_workqueue+0x108/0x21b
[ 113.553289] [<ffffffff80252303>] ? run_workqueue+0xb6/0x21b
[ 113.553289] [<ffffffffa018bcd2>] ? laundromat_main+0x0/0x24e [nfsd]
[ 113.553289] [<ffffffff8025254d>] worker_thread+0xe5/0xf6
[ 113.553289] [<ffffffff80256615>] ? autoremove_wake_function+0x0/0x3d
[ 113.553289] [<ffffffff80252468>] ? worker_thread+0x0/0xf6
[ 113.553289] [<ffffffff80256200>] kthread+0x4e/0x7b
[ 113.553289] [<ffffffff8020d51a>] child_rip+0xa/0x20
[ 113.553289] [<ffffffff8020cec0>] ? restore_args+0x0/0x30
[ 113.553289] [<ffffffff802561b2>] ? kthread+0x0/0x7b
[ 113.553289] [<ffffffff8020d510>] ? child_rip+0x0/0x20
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