mesa: Guard against null pointer deref in fbo validation

This matches the behaviour below when numSamples is compared.

At least with the gallium state tracker this can actually occur if st_render_texture fails.

Signed-off-by: Brian Paul <brianp@vmware.com>

diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
index f0065ad..eb1fef5 100644 (file)
--- a/src/mesa/main/fbobject.c
+++ b/src/mesa/main/fbobject.c
@@ -746,7 +746,7 @@ _mesa_test_framebuffer_completeness(struct gl_context *ctx,
          continue;
       }
 
-      if (numSamples < 0) {
+      if (att->Renderbuffer && numSamples < 0) {
          /* first buffer */
          numSamples = att->Renderbuffer->NumSamples;
       }