Re: [Scst-devel] BUG: Process hang when kvm crashed, stacktrace cfs+kvm

From: kordex
Date: Sat Jan 21 2012 - 16:19:29 EST


On Sat, Jan 21, 2012 at 18:11, Bart Van Assche <bvanassche@xxxxxxx> wrote:
> On Sat, Jan 21, 2012 at 2:58 PM, kordex <kordex@xxxxxxxxx> wrote:
>> On Thu, Jan 19, 2012 at 21:12, kordex <kordex@xxxxxxxxx> wrote:
>> > On Thu, Jan 19, 2012 at 20:34, kordex <kordex@xxxxxxxxx> wrote:
>> >> Full dmesg of the case attached.
>> >> On Thu, Jan 19, 2012 at 13:12, Bart Van Assche <bvanassche@xxxxxxx> wrote:
>> >>> On Thu, Jan 19, 2012 at 11:54 AM, kordex <kordex@xxxxxxxxx> wrote:
>> >>>> > root@teletex:/usr/src/linux# dmesg
>> >>>> > +0x12e7/0x1c50
>> >>>> > Â[<ffffffff810dc322>] ? page_add_new_anon_rmap+0x52/0xa0
>> >>>
>> >>> The above output is truncated - the most interesting part is missing.
>>
>> Do I need to give you anything else? Any leads on what the problem
>> might be? The machine is still running and in this state.
>
> In the /proc/meminfo output I see that the system has 16 GB RAM and 33
> GB swap memory. Also, MemFree + Buffers = 400 KB, which makes me
> assume the system was under heavy memory pressure ?
>
> Some essential information is still missing - the reason why the
> kernel started spewing out all these call traces. Did someone hit the
> SysRq key ? Is it because a task was hanging ? Was a BUG or WARNING
> hit ?
>
> Bart.

I hit sysrq+t sysrq+p in order to print the tasks with stacktraces and
registers. Using ps -e -o pid,state,command will hang ps output,
while ps -e -o pid,state will not.

Last line out from ps -ef is:
3102 S /usr/sbin/console-kit-daemon --no-daemon
Next one should be:
kordex@teletex:/proc$ cat 4119/comm
kvm
Doing root@teletex:/proc/4119# cat environ or cat cmdline will hang
the terminal, just like with ps.

About the memory usage:
kordex@teletex:~$ cat /proc/sys/vm/swappiness
60
kordex@teletex:~$ free -m
total used free shared buffers cached
Mem: 15965 15833 131 0 133 29
-/+ buffers/cache: 15670 294
Swap: 32767 3366 29401

top processes sorted by memory usage:

top - 23:03:07 up 20 days, 2:53, 4 users, load average: 81.08, 79.74, 78.75
Tasks: 278 total, 1 running, 275 sleeping, 0 stopped, 2 zombie
Cpu(s): 2.1%us, 1.7%sy, 0.0%ni, 48.1%id, 48.1%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 16348324k total, 16214044k used, 134280k free, 137012k buffers
Swap: 33554428k total, 3447372k used, 30107056k free, 30080k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
10150 libvirt- 20 0 4584m 3.1g 740 S 2 19.6 678:53.51 kvm
6051 libvirt- 20 0 4489m 1.8g 676 S 3 11.5 6046:48 kvm
9853 libvirt- 20 0 3568m 43m 824 S 6 0.3 891:26.22 kvm
6291 libvirt- 20 0 2047m 327m 480 S 2 2.1 294:26.91 kvm
7273 libvirt- 20 0 1874m 15m 1812 D 0 0.1 0:00.09 kvm
5423 libvirt- 20 0 1105m 7880 412 S 0 0.0 256:52.54 kvm
6915 libvirt- 20 0 1023m 129m 356 S 0 0.8 327:47.85 kvm
5921 libvirt- 20 0 994m 61m 348 S 2 0.4 335:29.19 kvm
4119 libvirt- 20 0 961m 99m 372 D 0 0.6 470:42.29 kvm
6873 libvirt- 20 0 575m 101m 672 S 2 0.6 328:05.80 kvm
6166 libvirt- 20 0 567m 11m 344 S 0 0.1 275:25.91 kvm
6642 libvirt- 20 0 560m 92m 376 D 0 0.6 269:03.14 kvm
4225 libvirt- 20 0 548m 7312 76 S 3 0.0 335:52.23 kvm
4352 libvirt- 20 0 525m 13m 520 S 3 0.1 344:22.53 kvm
6726 libvirt- 20 0 519m 116m 372 S 3 0.7 352:13.64 kvm
6964 libvirt- 20 0 464m 91m 504 S 3 0.6 337:30.12 kvm

Br,
-Mikko Kortelainen
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