Re: Fwd: failure notice

[Tom Kacvinsky <tom dot kacvinsky at vectorcast dot com>]

On Tue, Dec 8, 2015 at 11:55 AM, Tom Kacvinsky
<tom.kacvinsky@vectorcast.com> wrote:
> On Tue, Dec 8, 2015 at 11:49 AM, Jon Turney <jon.turney@dronecode.org.uk> wrote:
>> On 07/12/2015 16:17, Tom Kacvinsky wrote:
>>>
>>> On Mon, Dec 7, 2015 at 10:24 AM, Tom Kacvinsky wrote:
>>>>
>>>> On Mon, Dec 7, 2015 at 10:19 AM, Jon Turney wrote:
>>>>>
>>>>> On 04/12/2015 14:20, Tom Kacvinsky wrote:
>>>>>>
>>>>>> We have an interesting problem whereby an Linux X client application
>>>>>> crashes when running the X server on cygwin.  We have a reproducer
>>>>>> for the problem, but it is a Qt example application stored in a
>>>>>> tarball.
>>>>>>
>>>>>> We have gathered the other information that would typically be
>>>>>> requested.
>>>>>> I just need to know the best way of getting this information to the
>>>>>> list.
>>>>>
>>>>>
>>>>>
>>>>> If the tarball is being rejected by the mailing list, I'd suggest you
>>>>> upload
>>>>> it to some file hosting site and send a link to the mailing list.
>>>>>
>>>>> If that is really not possible for you (why?), you may, on this specific
>>>>> occasion only, mail it directly to me.
>>>>
>>>>
>>>> Hi Jon,
>>>>
>>>> That is totally do-able.  I will get it on a hosting site and send the
>>>> link.
>>>
>>>
>>> Here is the DropBox link.
>>>
>>> https://www.dropbox.com/s/b6exaxm30j8q318/cygwin-x-repro.zip?dl=0
>>
>>
>> Sorry, I hadn't noticed that you are describing a crash in the Qt client,
>> not the Cygwin X server.
>>
>> So, firstly, this is a Qt issue.

It could be, since you aren't able to reproduce with Qt 4.8.1, but we can
with 4.8.5 that we built.  See below.

>>
>> It may well be that the multiwindow mode window manager for the Cygwin X
>> server doesn't satisfy some expectation that Qt has (and I would be
>> interested to know what that is), but Qt crashing is never the right
>> thing to do.
>>
>> A backtrace of the Qt client when it crashes might be informative.
>>
>
> Will attempt to get one.  I recall seeing in our internal bug tracking system
> the exact X server error message.  Would that be of use?
>

There is no hard crash with a core dump so I can't get a backtrace.  The client
dies with no diagnostics - the GUI goes away and we return to the command
prompt.

>>> Please note it is a Qt reproducer.  We have some hard coded paths in
>>> the Makefile that you will need to modify.  We are using Qt 4.8.6
>>> built on Ubuntu 12.04, 32 bit.
>>
>> Nevertheless, I tried your reproducer in a Ubuntu 12.04 32-bit VM, but
>> wasn't able to observe any crash.
>>
>> I note that an Ubuntu 12.04 only seems to have Qt 4.8.1.  Are you using a
>> self-built Qt?
>
> Yes, we are using a self built Qt, pretty much a stock build, only thing we are
> not doing is building the examples and demos.
>

We can provide the libraries we built and you can set LD_LIBRARY_PATH
accordingly.

Tom

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