[Mesa-users] Segmentation fault in "Fake_glXUseXFont" (Mesa 10.4.3)

[Brian Paul]

On 02/25/2015 08:18 AM, Martin Knoblauch wrote:
> Hi,
>
>   in a customer project I am facing an awkward situation. We need to run
> a "closed source 3rd party interactive OpenGL application with 'not very
> good support'" (I cannot and do not want to name the App) on a server
> machine with no dedicated GFX hardware.
>
>   The plan is to run it with Mesa OpenGL and a Xvfb X server.
>
> This mostly works OK, but we are seeing consistent segmentation faults
> whenever "glXUseFont" is called. The core dumps come from line the
> following lines in the "Fake_glXUseXFont" routine:
>
>                  dpy = glXGetCurrentDisplay();
>                  if (!dpy)
>                      return;                   /* I guess glXMakeCurrent
> wasn't called */
> core ==>   win = RootWindow(dpy, DefaultScreen(dpy));
>
> So the call to "glXGetCurrentDisplay" returns non-null, but the
> structure behind the pointer seems invalid. I added some debugging
> output, and that shows that the "number of screens" for that display is
> 0, which explains the failure in the RootWindow macro.
>
>   Now the questions are:
>
> 1) how cant that happen
> 2) what can be done

OK, I just reproduced the issue here.  I think it's been broken for a 
long time.  Can you try the attached Mesa patch?


>
> The server is running SLES11SP2 and Mesa has been build with the
> following configure options:
>
>    $ ./configure --enable-driglx-direct --enable-xlib-glx --disable-dri
> --disable-xvmc --disable-egl --with-gallium-drivers=

I'd omit --enable-driglx-direct, that seems in conflict with wanting to 
use Xlib rather than DRI.

-Brian

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