st/mesa: add null pointer check in st_renderbuffer_delete()

In my testing I haven't found any cases where we get a null context
pointer, but it might still be possible.  Check for null just to be safe.

Note: This is a candidate for the stable branches.
(cherry picked from commit a4311054c78536acba0c3006c5d2805e182fa483)

1 files changed, 4 insertions, 4 deletions

diff --git a/src/mesa/state_tracker/st_cb_fbo.c b/src/mesa/state_tracker/st_cb_fbo.c
index 755697c0a9..2b2c1fbeb6 100644
--- a/src/mesa/state_tracker/st_cb_fbo.c
+++ b/src/mesa/state_tracker/st_cb_fbo.c
@@ -228,10 +228,10 @@ static void
 st_renderbuffer_delete(struct gl_context *ctx, struct gl_renderbuffer *rb)
 {
    struct st_renderbuffer *strb = st_renderbuffer(rb);
-   struct st_context *st = st_context(ctx);
-   struct pipe_context *pipe = st->pipe;
-
-   pipe_surface_release(pipe, &strb->surface);
+   if (ctx) {
+      struct st_context *st = st_context(ctx);
+      pipe_surface_release(st->pipe, &strb->surface);
+   }
    pipe_resource_reference(&strb->texture, NULL);
    free(strb->data);
    _mesa_delete_renderbuffer(ctx, rb);