On 07/22/2015 04:03 PM, Nikolay Aleksandrov wrote:
> On 07/22/2015 03:58 PM, Florian Westphal wrote:
>> Nikolay Aleksandrov <niko...@cumulusnetworks.com> wrote:
>>> On 07/22/2015 10:17 AM, Frank Schreuder wrote:
>>>> I got some additional information from syslog:
>>>>
>>>> Jul 22 09:49:33 dommy0 kernel: [ 675.987890] NMI watchdog: BUG: soft
>>>> lockup - CPU#3 stuck for 22s! [kworker/3:1:42]
>>>> Jul 22 09:49:42 dommy0 kernel: [ 685.114033] INFO: rcu_sched
>>>> self-detected stall on CPU { 3} (t=39918 jiffies g=988 c=987 q=23168)
>>>>
>>>> Thanks,
>>>> Frank
>>>>
>>>>
>>>
>>> Hi,
>>> It looks like it's happening because of the evict_again logic, I think we
>>> should also
>>> add Florian's first suggestion about simplifying it to the patch and just
>>> skip the
>>> entry if we can't delete its timer otherwise we can restart the eviction
>>> and see
>>> entries that already had their timer stopped by us and can keep restarting
>>> for
>>> a long time.
>>> Here's an updated patch that removes the evict_again logic.
>>
>> Thanks Nik. I'm afraid this adds bug when netns is exiting.
>>
>> Currently, we wait until timer has finished, but after the change
>> we might destroy percpu counter while a timer is still executing on
>> another cpu.
>>
>> I pushed a patch series to
>> https://git.breakpoint.cc/cgit/fw/net.git/log/?h=inetfrag_fixes_02
>>
>> It includes this patch with a small change -- deferral of the percpu
>> counter subtraction until after queue has been free'd.
>>
>> Frank -- it would be great if you could test with the four patches in
>> that series applied.
>>
>> I'll then add your tested-by Tag to all of them before submitting this.
>>
>> Thanks again for all your help in getting this fixed!
>>
>
> Sure, I didn't think it through, just supplied it for the test. :-)
> Thanks for fixing it up!
>
Patches look great, even the INET_FRAG_EVICTED flag will not be accidentally
cleared
this way. I'll give them a try.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
