From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: autofs4 hang in 2.6.37-rc1
Date: Sun, 14 Nov 2010 15:51:04 +0200
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To: Ian Kent <raven@themaw.net>, autofs@linux.kernel.org
Cc: linux-kernel <linux-kernel@vger.kernel.org>

On 11/14/2010 02:55 PM, Avi Kivity wrote:
> A 2.6.37-rc1 (f6614b7bb405a) setup hangs in autofs4:
>
> INFO: task automount:10399 blocked for more than 120 seconds.
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> automount     D 0000000000000000     0 10399      1 0x00000000
>  ffff88012a059da8 0000000000000082 0000000000000000 0000000000000000
>  ffff88012a058010 ffff88012a059fd8 0000000000011800 ffff8801290f2c40
>  ffff8801290f2fb0 ffff8801290f2fa8 0000000000011800 0000000000011800
> Call Trace:
>  [<ffffffff813a3c3c>] __mutex_lock_common+0x126/0x18b
>  [<ffffffff813a3cb5>] __mutex_lock_slowpath+0x14/0x16
>  [<ffffffff813a3dbc>] mutex_lock+0x31/0x4b
>  [<ffffffff811b17f7>] autofs4_root_ioctl+0x28/0x53
>  [<ffffffff810f5e5c>] do_vfs_ioctl+0x557/0x5bb
>  [<ffffffff810eca65>] ? sys_newlstat+0x2d/0x38
>  [<ffffffff810f5f02>] sys_ioctl+0x42/0x65
>  [<ffffffff81002b42>] system_call_fastpath+0x16/0x1b
>
> This is a simple /home automount.  More info on request.
>

Likely culprit:


automount     S ffff88012a28a680     0   399      1 0x00000000
  ffff88012a07bd08 0000000000000082 0000000000000000 0000000000000000
  ffff88012a07a010 ffff88012a07bfd8 0000000000011800 ffff88012693c260
  ffff88012693c5d0 ffff88012693c5c8 0000000000011800 0000000000011800
Call Trace:
  [<ffffffff81056197>] ? prepare_to_wait+0x67/0x74
  [<ffffffff811b23eb>] autofs4_wait+0x5a4/0x6d5
  [<ffffffff81055f25>] ? autoremove_wake_function+0x0/0x34
  [<ffffffff811b2ba5>] autofs4_do_expire_multi+0x5b/0xa3
  [<ffffffff811b2c39>] autofs4_expire_multi+0x4c/0x54
  [<ffffffff811b1750>] autofs4_root_ioctl_unlocked+0x23e/0x252
  [<ffffffff811b1808>] autofs4_root_ioctl+0x39/0x53
  [<ffffffff810f5e5c>] do_vfs_ioctl+0x557/0x5bb
  [<ffffffff810ca644>] ? remove_vma+0x6e/0x76
  [<ffffffff810cb6a2>] ? do_munmap+0x31c/0x33e
  [<ffffffff810f5f02>] sys_ioctl+0x42/0x65
  [<ffffffff81002b42>] system_call_fastpath+0x16/0x1b


Shouldn't we drop autofs4_ioctl_mutex while we wait?

-- 
error compiling committee.c: too many arguments to function