[Mesa-dev] VTK Offscreen Segfaults

[Brian Paul]

On 08/05/2010 04:30 PM, tom fogal wrote:
> "Kevin H. Hobbs"<hobbsk at ohiou.edu>  writes:
>> On 08/04/2010 05:58 PM, tom fogal wrote:
>>> If you can find the commit that started the trouble (using git
>>> bisect), that might shed some light.
>>
>> With my script adjusted to only report when the test started
>> segfaulting git bisect reports :
>>
>> 91c37599f621a0ec498c0f0add14f16470ca852b is the first bad commit
>> commit 91c37599f621a0ec498c0f0add14f16470ca852b
>> Author: Brian Paul<brianp at vmware.com>
>> Date:   Fri Jul 2 18:18:15 2010 -0600
>>
>>      osmesa: remove old renderbuffer before adding new
>>    =20
>>      Fixes fd.o bug 10966 when OSMesaMakeCurrent() was called twice.
>>    =20
>>      NOTE: This is a candidate for the 7.8 branch.
>
> Well, that sucks.  I just started putting together commits for 7.8
> recently, specifically because I/we need *that* one commit ;)
>
> Is your test multithreaded, by any chance?
>
> It looked like some sort of strange link/memory corruption to me
> before, but valgrind didn't turn up much, and this commit really does
> so little; it seems odd to blame memory corruption in this case.
> Brian, any ideas?

Yeah, this is weird.

Kevin, you seem to have identified two potential commits that caused 
trouble:

91c37599f621a0ec498c0f0add14f16470ca852b
and
36b3a8bd5a317ab297f44b19fd14c7e76ec2fc77

You should go to the head of the Mesa git tree and then undo each of 
those changes one by one (either git-revert or patch -R, etc) and 
re-test to be absolutely sure that one or the other is causing the 
segfault.

My other hunch is something is duplicated in the libOSMesa and libGL 
libraries that's causing things to blow up in general.

-Brian