[Mono-dev] Regressions on 3.13.0-46-generic -> 3.13.0-48-generic

[Greg Young]

I am surprised to see no one else post on this.

I would think a massive regression that prevents mono from running
multi-threaded code on a multi-cpu system (including in the future on
any v4 kernel) might be an issue that people would be concerned
about?!



On Thu, Sep 17, 2015 at 4:03 PM, Greg Young <gregoryyoung1 at gmail.com> wrote:
> So to follow up on this.
>
> The fix that was put in for this has since been reverted as mentioned
> in the bug above.
>
> https://github.com/torvalds/linux/commit/73459e2a1ada09a68c02cc5b73f3116fc8194b3d
>
> So all 4 kernels will have this issue. I'm not really sure what needs
> to be done on the mono side here to avoid this issue but it would seem
> to affect any multi-threaded code running on multiple cpu linux
> systems (which I would imagine would be a vast majority of mono
> installations).
>
> Greg
>
> On Thu, Sep 17, 2015 at 1:05 PM, Greg Young <gregoryyoung1 at gmail.com> wrote:
>> I was just actually writing that this seems to be discussed here:
>> https://bugzilla.xamarin.com/show_bug.cgi?id=29692 :) Thanks for the
>> additional information.
>>
>>
>>
>> On Thu, Sep 17, 2015 at 1:01 PM, Taloth Saldono <talothsaldono at gmail.com> wrote:
>>> This Ubuntu bug discusses the issue for 3.13.
>>> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1450584
>>>
>>> Please note that later kernel 4.0 versions exhibit similar issues, search
>>> this mailinglist for specifics on that new regression. I gave up on
>>> investigating further due to other obligations and the complexity of the
>>> subject matter.
>>>
>>> Op 17 sep. 2015 11:49 schreef "Greg Young" <gregoryyoung1 at gmail.com>:
>>>>
>>>> 3.13.0-63-generic does not have the issue as well.
>>>>
>>>> I guess our mitigation will just be to know about the issue and
>>>> suggest downgrade/upgrade. This may however be useful for others in
>>>> the future. Mono 3.12.1 on 3.13.0-46-generic #77-Ubuntu SMP appears to
>>>> not be stable. We will also test mono4 now.
>>>>
>>>> Greg
>>>>
>>>> On Thu, Sep 17, 2015 at 11:38 AM, Greg Young <gregoryyoung1 at gmail.com>
>>>> wrote:
>>>> > We are running into some interesting regressions with mono. We are
>>>> > seeing many failures such as:
>>>> >
>>>> > Mono v3.12.1 (we have considered moving up to 4.1 or 4.2 but the last
>>>> > time we tested it didn't seem safe to move).
>>>> >
>>>> > Native stacktrace:
>>>> >
>>>> > /home/ubuntu/EventStore-OSS-Ubuntu-v3.2.1/eventstored() [0x609a4f]
>>>> > /home/ubuntu/EventStore-OSS-Ubuntu-v3.2.1/eventstored() [0x5bdecf]
>>>> > /home/ubuntu/EventStore-OSS-Ubuntu-v3.2.1/eventstored() [0x453b19]
>>>> > /lib/x86_64-linux-gnu/libpthread.so.0(+0x10340) [0x7fd9709b7340]
>>>> > /home/ubuntu/EventStore-OSS-Ubuntu-v3.2.1/eventstored() [0x4e6145]
>>>> > [0x40e21ceb]
>>>> >
>>>> >
>>>> > [03041,21,13:43:11.379] Global Unhandled Exception occurred.
>>>> > Object reference not set to an instance of an object
>>>> > [ERROR] FATAL UNHANDLED EXCEPTION: System.NullReferenceException:
>>>> > Object reference not set to an instance of an object
>>>> >   at EventStore.Core.Bus.QueuedHandlerAutoReset.ReadFromQueue
>>>> > (System.Object o) [0x00000] in <filename unknown>:0
>>>> >   at System.Threading.Thread.StartInternal () [0x00000] in <filename
>>>> > unknown>:0
>>>> >
>>>> > note that this isn't a real nre
>>>> >
>>>> > We do not see these regressions in Linux ip-172-31-37-60
>>>> > 3.13.0-46-generic #77-Ubuntu SMP
>>>> >
>>>> > We do see them in Linux ip-172-31-40-115 3.13.0-48-generic #80-Ubuntu
>>>> > SMP
>>>> >
>>>> > Anyone have any ideas how to debug this further? These are not
>>>> > deterministic issues.
>>>> >
>>>> > Cheers,
>>>> >
>>>> > Greg
>>>> >
>>>> > --
>>>> > Studying for the Turing test
>>>>
>>>>
>>>>
>>>> --
>>>> Studying for the Turing test
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>>
>>
>>
>> --
>> Studying for the Turing test
>
>
>
> --
> Studying for the Turing test



-- 
Studying for the Turing test