* 2.6.39-rc0: umount tmpfs hangs
@ 2011-03-21 2:24 Alexander Beregalov
2011-03-21 3:39 ` Al Viro
0 siblings, 1 reply; 5+ messages in thread
From: Alexander Beregalov @ 2011-03-21 2:24 UTC (permalink / raw)
To: Linux Kernel Mailing List, Al Viro
Hi
kernel is 2.6.38-06507-ga952baa
/etc/init.d/swap stop
runs
umount -a -t tmpfs
which is hangs at
$cat /proc/4453/stack
[<c1066332>] rcu_barrier_sched+0x32/0x40
[<c109fdca>] deactivate_locked_super+0x3a/0x60
[<c10a05f6>] deactivate_super+0x46/0x60
[<c10b6f2a>] mntput_no_expire+0x5a/0x90
[<c10b7a6d>] sys_umount+0x5d/0x300
[<c10b7d29>] sys_oldumount+0x19/0x20
[<c136eb50>] sysenter_do_call+0x12/0x36
[<ffffffff>] 0xffffffff
INFO: task umount:4453 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
umount D 00000000 5400 4453 4446 0x00000000
d87cfe24 00000046 00000000 00000000 00000424 00000000 00000424 c19f0418
d87cfe24 d87c3d20 286b9967 0000007f d87c3d20 0000007f c17d3970 edb07b89
000000ec 00000092 d87cfe2c c1047882 28a482c8 0000007f 28a45c7b 0000007f
Call Trace:
[<c1047882>] ? sched_clock_local.clone.1+0x42/0x1a0
[<c1367585>] schedule_timeout+0x125/0x1b0
[<c1047a9d>] ? sched_clock_cpu+0x7d/0xf0
[<c10518eb>] ? trace_hardirqs_off+0xb/0x10
[<c1369b02>] ? _raw_spin_unlock_irq+0x22/0x30
[<c105431b>] ? trace_hardirqs_on+0xb/0x10
[<c13672d5>] wait_for_common+0xd5/0x130
[<c1021a80>] ? default_wake_function+0x0/0x10
[<c13673d2>] wait_for_completion+0x12/0x20
[<c1066332>] rcu_barrier_sched+0x32/0x40
[<c103f5b0>] ? wakeme_after_rcu+0x0/0x10
[<c1367231>] ? wait_for_common+0x31/0x130
[<c109fdca>] deactivate_locked_super+0x3a/0x60
[<c10a05f6>] deactivate_super+0x46/0x60
[<c10b6f2a>] mntput_no_expire+0x5a/0x90
[<c10b7a6d>] sys_umount+0x5d/0x300
[<c10b7d29>] sys_oldumount+0x19/0x20
[<c136eb50>] sysenter_do_call+0x12/0x36
no locks held by umount/4453.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: 2.6.39-rc0: umount tmpfs hangs
2011-03-21 2:24 2.6.39-rc0: umount tmpfs hangs Alexander Beregalov
@ 2011-03-21 3:39 ` Al Viro
2011-03-21 5:30 ` Alexander Beregalov
0 siblings, 1 reply; 5+ messages in thread
From: Al Viro @ 2011-03-21 3:39 UTC (permalink / raw)
To: Alexander Beregalov; +Cc: Linux Kernel Mailing List
On Mon, Mar 21, 2011 at 05:24:08AM +0300, Alexander Beregalov wrote:
> Hi
>
> kernel is 2.6.38-06507-ga952baa
>
> /etc/init.d/swap stop
> runs
> umount -a -t tmpfs
>
> which is hangs at
>
> $cat /proc/4453/stack
> [<c1066332>] rcu_barrier_sched+0x32/0x40
> [<c109fdca>] deactivate_locked_super+0x3a/0x60
> [<c10a05f6>] deactivate_super+0x46/0x60
> [<c10b6f2a>] mntput_no_expire+0x5a/0x90
> [<c10b7a6d>] sys_umount+0x5d/0x300
> [<c10b7d29>] sys_oldumount+0x19/0x20
> [<c136eb50>] sysenter_do_call+0x12/0x36
> [<ffffffff>] 0xffffffff
rcu_barrier() hanging for some reason... I really wonder what's going
on there - missing rcu_read_unlock()? Could you try to reproduce that
sucker and, if possible, bisect it?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: 2.6.39-rc0: umount tmpfs hangs
2011-03-21 3:39 ` Al Viro
@ 2011-03-21 5:30 ` Alexander Beregalov
2011-03-21 5:54 ` Al Viro
0 siblings, 1 reply; 5+ messages in thread
From: Alexander Beregalov @ 2011-03-21 5:30 UTC (permalink / raw)
To: Al Viro; +Cc: Linux Kernel Mailing List
On 21 March 2011 06:39, Al Viro <viro@zeniv.linux.org.uk> wrote:
> On Mon, Mar 21, 2011 at 05:24:08AM +0300, Alexander Beregalov wrote:
>> Hi
>>
>> kernel is 2.6.38-06507-ga952baa
>>
>> /etc/init.d/swap stop
>> runs
>> umount -a -t tmpfs
>>
>> which is hangs at
>>
>> $cat /proc/4453/stack
>> [<c1066332>] rcu_barrier_sched+0x32/0x40
>> [<c109fdca>] deactivate_locked_super+0x3a/0x60
>> [<c10a05f6>] deactivate_super+0x46/0x60
>> [<c10b6f2a>] mntput_no_expire+0x5a/0x90
>> [<c10b7a6d>] sys_umount+0x5d/0x300
>> [<c10b7d29>] sys_oldumount+0x19/0x20
>> [<c136eb50>] sysenter_do_call+0x12/0x36
>> [<ffffffff>] 0xffffffff
>
> rcu_barrier() hanging for some reason... I really wonder what's going
> on there - missing rcu_read_unlock()? Could you try to reproduce that
> sucker and, if possible, bisect it?
Yes, it's reproducible, but I'm bisecting another issue and have few
more such issues with the current kernel.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: 2.6.39-rc0: umount tmpfs hangs
2011-03-21 5:30 ` Alexander Beregalov
@ 2011-03-21 5:54 ` Al Viro
2011-03-21 6:18 ` Alexander Beregalov
0 siblings, 1 reply; 5+ messages in thread
From: Al Viro @ 2011-03-21 5:54 UTC (permalink / raw)
To: Alexander Beregalov; +Cc: Linux Kernel Mailing List
On Mon, Mar 21, 2011 at 08:30:23AM +0300, Alexander Beregalov wrote:
> > rcu_barrier() hanging for some reason... ??I really wonder what's going
> > on there - missing rcu_read_unlock()? ??Could you try to reproduce that
> > sucker and, if possible, bisect it?
>
> Yes, it's reproducible, but I'm bisecting another issue and have few
> more such issues with the current kernel.
Could you post the reproducer? Simple mounting tmpfs and umount explicitly
doesn't seem to trigger it; doing some IO on that fs doesn't change that,
ditto for umount done by shutdown instead of doing it manually...
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: 2.6.39-rc0: umount tmpfs hangs
2011-03-21 5:54 ` Al Viro
@ 2011-03-21 6:18 ` Alexander Beregalov
0 siblings, 0 replies; 5+ messages in thread
From: Alexander Beregalov @ 2011-03-21 6:18 UTC (permalink / raw)
To: Al Viro; +Cc: Linux Kernel Mailing List
On 21 March 2011 08:54, Al Viro <viro@zeniv.linux.org.uk> wrote:
> On Mon, Mar 21, 2011 at 08:30:23AM +0300, Alexander Beregalov wrote:
>
>> > rcu_barrier() hanging for some reason... ??I really wonder what's going
>> > on there - missing rcu_read_unlock()? ??Could you try to reproduce that
>> > sucker and, if possible, bisect it?
>>
>> Yes, it's reproducible, but I'm bisecting another issue and have few
>> more such issues with the current kernel.
>
> Could you post the reproducer? Simple mounting tmpfs and umount explicitly
> doesn't seem to trigger it; doing some IO on that fs doesn't change that,
> ditto for umount done by shutdown instead of doing it manually...
For me it is just shutting down.
While bisecting another issue I found this range for bisection:
ceda86a108671294052cbf51660097b6534672f5 good
7a6362800cb7d1d618a697a650c7aaed3eb39320 bad
but only if the bug is 100% reproducible with my test, I can't be sure yet.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2011-03-21 6:18 UTC | newest]
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2011-03-21 2:24 2.6.39-rc0: umount tmpfs hangs Alexander Beregalov
2011-03-21 3:39 ` Al Viro
2011-03-21 5:30 ` Alexander Beregalov
2011-03-21 5:54 ` Al Viro
2011-03-21 6:18 ` Alexander Beregalov
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