mesa: fix crash in st/mesa after deleting a VAO

This happens when glGetMultisamplefv (or any other non-draw function) is
called, which doesn't invoke the VBO module to update _DrawArrays and
the pointer is invalid at that point.

However st/mesa still dereferences it to setup vertex buffers ==> crash.

Reviewed-by: Brian Paul <[email protected]>

2 files changed, 4 insertions, 33 deletions

diff --git a/src/mesa/vbo/vbo_context.h b/src/mesa/vbo/vbo_context.h
index 1680e23dcf3..e2245130575 100644
--- a/src/mesa/vbo/vbo_context.h
+++ b/src/mesa/vbo/vbo_context.h
@@ -57,18 +57,6 @@
 #include "vbo_save.h"
 
 
-/** Used to signal when transitioning from one kind of drawing method
- * to another.
- */
-enum draw_method
-{
-   DRAW_NONE,          /**< Initial value only */
-   DRAW_BEGIN_END,
-   DRAW_DISPLAY_LIST,
-   DRAW_ARRAYS
-};
-
-
 struct vbo_context {
    struct gl_client_array currval[VBO_ATTRIB_MAX];
    
@@ -83,8 +71,6 @@ struct vbo_context {
     * is responsible for initiating any fallback actions required:
     */
    vbo_draw_func draw_prims;
-
-   enum draw_method last_draw_method;
 };
 
 
@@ -122,11 +108,11 @@ get_program_mode( struct gl_context *ctx )
  * that arrays may be changing.
  */
 static inline void
-vbo_draw_method(struct vbo_context *vbo, enum draw_method method)
+vbo_draw_method(struct vbo_context *vbo, gl_draw_method method)
 {
-   if (vbo->last_draw_method != method) {
-      struct gl_context *ctx = vbo->exec.ctx;
+   struct gl_context *ctx = vbo->exec.ctx;
 
+   if (ctx->Array.DrawMethod != method) {
       switch (method) {
       case DRAW_ARRAYS:
          ctx->Array._DrawArrays = vbo->exec.array.inputs;
@@ -142,7 +128,7 @@ vbo_draw_method(struct vbo_context *vbo, enum draw_method method)
       }
 
       ctx->NewDriverState |= ctx->DriverFlags.NewArray;
-      vbo->last_draw_method = method;
+      ctx->Array.DrawMethod = method;
    }
 }
 
diff --git a/src/mesa/vbo/vbo_exec.c b/src/mesa/vbo/vbo_exec.c
index bd2b1b1a9df..eb903504328 100644
--- a/src/mesa/vbo/vbo_exec.c
+++ b/src/mesa/vbo/vbo_exec.c
@@ -82,21 +82,6 @@ void vbo_exec_invalidate_state( struct gl_context *ctx, GLuint new_state )
 
    if (!exec->validating && new_state & (_NEW_PROGRAM|_NEW_ARRAY)) {
       exec->array.recalculate_inputs = GL_TRUE;
-
-      /* If we ended up here because a VAO was deleted, the _DrawArrays
-       * pointer which pointed to the VAO might be invalid now, so set it
-       * to NULL.  This prevents crashes in driver functions like Clear
-       * where driver state validation might occur, but the vbo module is
-       * still in an invalid state.
-       *
-       * Drivers should skip vertex array state validation if _DrawArrays
-       * is NULL.  It also has no effect on performance, because attrib
-       * bindings will be recalculated anyway.
-       */
-      if (vbo->last_draw_method == DRAW_ARRAYS) {
-         ctx->Array._DrawArrays = NULL;
-         vbo->last_draw_method = DRAW_NONE;
-      }
    }
 
    if (new_state & _NEW_EVAL)