xlib: 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 <[email protected]>
(cherry picked from commit fd9fe4470be0437c18cbd6d2bc8e568378f88200)

1 files changed, 12 insertions, 10 deletions

diff --git a/src/mesa/drivers/x11/fakeglx.c b/src/mesa/drivers/x11/fakeglx.c
index c060711cac6..37b5e2f2b32 100644
--- a/src/mesa/drivers/x11/fakeglx.c
+++ b/src/mesa/drivers/x11/fakeglx.c
@@ -1532,16 +1532,18 @@ void _kw_ungrab_all( Display *dpy )
 static void
 Fake_glXDestroyContext( Display *dpy, GLXContext ctx )
 {
-   struct fake_glx_context *glxCtx = (struct fake_glx_context *) ctx;
-   (void) dpy;
-   MakeCurrent_PrevContext = 0;
-   MakeCurrent_PrevDrawable = 0;
-   MakeCurrent_PrevReadable = 0;
-   MakeCurrent_PrevDrawBuffer = 0;
-   MakeCurrent_PrevReadBuffer = 0;
-   XMesaDestroyContext( glxCtx->xmesaContext );
-   XMesaGarbageCollect(dpy);
-   free(glxCtx);
+   if (ctx) {
+      struct fake_glx_context *glxCtx = (struct fake_glx_context *) ctx;
+      (void) dpy;
+      MakeCurrent_PrevContext = 0;
+      MakeCurrent_PrevDrawable = 0;
+      MakeCurrent_PrevReadable = 0;
+      MakeCurrent_PrevDrawBuffer = 0;
+      MakeCurrent_PrevReadBuffer = 0;
+      XMesaDestroyContext( glxCtx->xmesaContext );
+      XMesaGarbageCollect(dpy);
+      free(glxCtx);
+   }
 }