Debugging stuck vdsm jobs

[Nir Soffer]

On Sun, May 29, 2016 at 2:10 AM, Nir Soffer <nsoffer at redhat.com> wrote:
> It look like this when tests times out:
>
> 23:04:44 miscTests.EventTests
> 23:04:44     testEmit                                                    OK
> 23:04:44     testEmitCallbackException                                   OK
> 23:04:49     testEmitStale                                               OK
> 23:04:49     testInstanceMethod                                          OK
> 23:04:50     testInstanceMethodDead                                      OK
> 23:04:55     testOneShot
> 23:04:55 ========================================================================
> 23:04:55 =           Timeout completing tests - extracting stacktrace
>          =
> 23:04:55 ========================================================================
> 23:04:55
> 23:04:55 attach: No such file or directory.
> 23:04:55 [New LWP 7887]
> 23:04:55 [New LWP 7880]
> 23:04:55 [New LWP 7873]
> 23:04:55 [New LWP 7866]
> 23:04:55 [New LWP 7859]
> 23:04:55 [New LWP 7852]
> 23:04:55 [New LWP 7845]
> 23:04:55 [Thread debugging using libthread_db enabled]
> 23:04:55 Using host libthread_db library "/lib64/libthread_db.so.1".
> 23:04:56 0x00007f17f0a1fa82 in pthread_cond_timedwait@@GLIBC_2.3.2 ()
> from /lib64/libpthread.so.0
> 23:04:56
> 23:04:56 Thread 8 (Thread 0x7f17df860700 (LWP 7845)):
> 23:04:56 Undefined command: "py-bt".  Try "help".
> 23:04:56 OK
> 23:04:56     testUnregister
> 23:04:56 ========================================================================
> 23:04:56 =                        Aborting tests
>          =
> 23:04:56 ========================================================================
> 23:04:56 ../tests/run_tests_local.sh: line 35:  7743 Killed
>       "$PYTHON_EXE" ../tests/testrunner.py --local-modules $@
>
>
>
> On Sun, May 29, 2016 at 2:07 AM, Nir Soffer <nsoffer at redhat.com> wrote:
>> On Thu, May 26, 2016 at 11:08 PM, Nir Soffer <nsoffer at redhat.com> wrote:
>>> Hi all,
>>>
>>> We had 2 issues causing vdsm check-patch and check-merge jobs to get stuck.
>>>
>>> I fixed the one that caused most trouble:
>>> https://gerrit.ovirt.org/57993
>>>
>>> The other issue may be related to ioprocess, I fixed a related issue:
>>> https://gerrit.ovirt.org/57473
>>>
>>> But I have seen stuck jobs after this change, so the issue may not
>>> be fixed yet.
>>>
>>> If you see a stuck vdsm job - job that run more than 15 minutes, please
>>> get me a backtrace:
>>>
>>> 1. locate the test_runner process pid:
>>>
>>>     $ ps aux | grep testrunner.py | grep -v grep
>>>     nsoffer  26297 82.6  0.9 389592 111144 pts/3   R+   22:52   0:02
>>> /usr/bin/python ../tests/testrunner.py ...
>>>
>>> 2. save a backtrace:
>>>
>>>     gdb attach 26297 --batch -ex "thread apply all py-bt" > py-bt.out
>>
>> This requires the python-debuginfo package, typically installed using:
>>
>>     dnf debuginfo-install python
>>
>> I sent this patch, detecting stuck vdsm tests, printing a backtrace, and killing
>> the stuck process:
>> https://gerrit.ovirt.org/58212
>>
>> It works, but we don't get a backtrace, since python-debuginfo is not installed
>> although I require it - probably we need to add the fedora-debug repository
>> to check-patch.repos. I tried to use the urls from /etc/yum.repos.d/fedora.repo,
>> but none of them work.
>>
>> I will need help from infra to get it working.

I sent also this patch, that should fix the issue on jenkins, but I
cannot test it on jenkins:
https://gerrit.ovirt.org/58213

Nir