st/glx: add null ctx check in glXDestroyContext()

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=64934
NOTE: This is a candidate for the stable branches.

Reviewed-by: Jose Fonseca <jfonseca@vmware.com>

diff --git a/src/gallium/state_trackers/glx/xlib/glx_api.c b/src/gallium/state_trackers/glx/xlib/glx_api.c
index a66ebc8e8a41c76bbc62ee8a51860dae68155fb5..c6dc134c5cf630e3906d236ae342ff051edee900 100644 (file)
--- a/src/gallium/state_trackers/glx/xlib/glx_api.c
+++ b/src/gallium/state_trackers/glx/xlib/glx_api.c
@@ -1353,16 +1353,18 @@ glXQueryExtension( Display *dpy, int *errorBase, int *eventBase )
 PUBLIC void
 glXDestroyContext( Display *dpy, GLXContext ctx )
 {
-   GLXContext glxCtx = ctx;
-   (void) dpy;
-   MakeCurrent_PrevContext = 0;
-   MakeCurrent_PrevDrawable = 0;
-   MakeCurrent_PrevReadable = 0;
-   MakeCurrent_PrevDrawBuffer = 0;
-   MakeCurrent_PrevReadBuffer = 0;
-   XMesaDestroyContext( glxCtx->xmesaContext );
-   XMesaGarbageCollect();
-   free(glxCtx);
+   if (ctx) {
+      GLXContext glxCtx = ctx;
+      (void) dpy;
+      MakeCurrent_PrevContext = 0;
+      MakeCurrent_PrevDrawable = 0;
+      MakeCurrent_PrevReadable = 0;
+      MakeCurrent_PrevDrawBuffer = 0;
+      MakeCurrent_PrevReadBuffer = 0;
+      XMesaDestroyContext( glxCtx->xmesaContext );
+      XMesaGarbageCollect();
+      free(glxCtx);
+   }
 }