qom/object: Don't poll cast cache for NULL objects

object_dynamic_cast_assert used to be tolerant of NULL objects and not assert. It's clear from the implementation that this is the expected behavior. The preceding check of the cast cache dereferences obj however causing a segfault. Fix by conditionalizing the cast cache logic on obj being non-null. Signed-off-by: Peter Crosthwaite <[email protected]> Reviewed-by: Andreas Färber <[email protected]> Reviewed-by: Anthony Liguori <[email protected]> Reviewed-by: Paolo Bonzini <[email protected]> Reviewed-by: Edgar E. Iglesias <[email protected]> Message-id: 8e2bef6a55753869c50bfa32226f7fcf0439ca62.1369183592.git.peter.crosthwaite@xilinx.com Signed-off-by: Anthony Liguori <[email protected]>
mslovy · May 22, 2013 · 95916ab · 95916ab
1 parent 3d1bba2
commit 95916ab
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/qom/object.c b/qom/object.c
@@ -442,7 +442,7 @@ Object *object_dynamic_cast_assert(Object *obj, const char *typename,
     int i;
     Object *inst;
 
-    for (i = 0; i < OBJECT_CLASS_CAST_CACHE; i++) {
+    for (i = 0; obj && i < OBJECT_CLASS_CAST_CACHE; i++) {
         if (obj->class->cast_cache[i] == typename) {
             goto out;
         }
@@ -458,7 +458,7 @@ Object *object_dynamic_cast_assert(Object *obj, const char *typename,
 
     assert(obj == inst);
 
-    if (obj == inst) {
+    if (obj && obj == inst) {
         for (i = 1; i < OBJECT_CLASS_CAST_CACHE; i++) {
             obj->class->cast_cache[i - 1] = obj->class->cast_cache[i];
         }