Re: Hung tasks related to do_filp_open in net-next (3.8.0-rc3+)

On 01/23/2013 01:38 PM, Ben Greear wrote:

I cranked up my 3000 NFS mounts test case on today's net-next (3.8.0-rc3+)
and about 8 of these splats.  There were around 780 mounts active
when these occurred.

Seems like the system continues OK, so not sure how important
this is...

I'm seeing this occasionally on 3.7.3 (plus Eric's patch to fix
the crashes I was seeing), so it's not a regression.

Maybe it's just expected on a very overloaded system....

Thanks,
Ben

INFO: task btserver:8756 blocked for more than 180 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
btserver        D 0000000000000004     0  8756   5781 0x00000080
  ffff880404ab1bf8 0000000000000046 0000000004ab1ba8 0000000000000432
  ffff880404ab0010 ffff880402263f20 ffff880404ab1fd8 00000000000132c0
  00000000000132c0 00000000000132c0 ffff880404ab1fd8 00000000000132c0
Call Trace:
  [<ffffffff815491ea>] schedule+0x5f/0x61
  [<ffffffff815494fa>] schedule_preempt_disabled+0x13/0x1f
  [<ffffffff81547ea8>] __mutex_lock_common+0x264/0x42d
  [<ffffffff8115fadb>] ? do_last+0x1db/0xa4e
  [<ffffffff8115fadb>] ? do_last+0x1db/0xa4e
  [<ffffffff815480d0>] mutex_lock_nested+0x16/0x18
  [<ffffffff8115fadb>] do_last+0x1db/0xa4e
  [<ffffffff8115f3a5>] ? path_init+0xcd/0x2b6
  [<ffffffff8116090b>] path_openat+0xcb/0x363
  [<ffffffff810d0055>] ? __lock_acquire+0x1df/0x53d
  [<ffffffff81160ca8>] do_filp_open+0x38/0x84
  [<ffffffff8154a2db>] ? _raw_spin_unlock+0x45/0x52
  [<ffffffff8116c203>] ? __alloc_fd+0x106/0x11a
  [<ffffffff815490f9>] ? __schedule+0x561/0x5a3
8021q: adding VLAN 0 to HW filter on device eth4#621
  [<ffffffff81153bfc>] do_sys_open+0x6d/0xff
8021q: adding VLAN 0 to HW filter on device eth3#612
  [<ffffffff81153cbb>] sys_open+0x1c/0x1e
  [<ffffffff8154f629>] system_call_fastpath+0x16/0x1b
2 locks held by btserver/8756:
  #0:  (sb_writers#10){......}, at: [<ffffffff81170013>] mnt_want_write+0x1f/0x48
  #1:  (&type->i_mutex_dir_key#4){......}, at: [<ffffffff8115fadb>] do_last+0x1db/0xa4e

-- 
Ben Greear [off-list ref]
Candela Technologies Inc  http://www.candelatech.com

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