Problem with programs/Xserver/GL/glx/glxcmds.c

["Willing, John (J.K.)" <jwilling@xxxxxxxx>]

Title: Problem with programs/Xserver/GL/glx/glxcmds.c

While running with a commercial CAD program, we encountered a problem with the OpenGL libraries.

In Function DoMakeCurrent
640   if (prevglxc) {
641      if (prevglxc->drawPixmap) {
642         if (prevglxc->drawPixmap != prevglxc->readPixmap) {
643                  /*
644                  ** The previous drawable was a glx pixmap, release it.
645                  */
646                  prevglxc->readPixmap->refcnt--;

We came across a problem where prevglxc->readPixmap is NULL causing a Segmentation Fault at line 646.  I resolved the issue by changing line 641 to:

641          if (prevglxc->drawPixmap && prevglxc->readPixmap) {

John Willing