st/mesa: check if _mesa_create_context() returns NULL

In some cases _mesa_create_context() can return NULL an in the mesa
state tracker, we do not concider the case, which may cause issues
within st_create_context_priv()

This patch adds a simple check (similar to the one in the dri drivers)

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Brian Paul <brianp@vmware.com>

diff --git a/src/mesa/state_tracker/st_context.c b/src/mesa/state_tracker/st_context.c
index 6eddbfc88e44a3c5b007790e88be5845202380b7..6d4bc544d0c336ca206ec93d7cc2141ea329c0cb 100644 (file)
--- a/src/mesa/state_tracker/st_context.c
+++ b/src/mesa/state_tracker/st_context.c
@@ -179,6 +179,9 @@ struct st_context *st_create_context(gl_api api, struct pipe_context *pipe,
    st_init_driver_functions(&funcs);
 
    ctx = _mesa_create_context(api, visual, shareCtx, &funcs, NULL);
+   if (!ctx) {
+      return NULL;
+   }
 
    /* XXX: need a capability bit in gallium to query if the pipe
     * driver prefers DP4 or MUL/MAD for vertex transformation.