diff --git a/daemon/util.h b/daemon/util.h
index cbc82cc..a20125e 100644
--- a/daemon/util.h
+++ b/daemon/util.h
@@ -117,13 +117,13 @@ static __inline void bitmap_unset(
 static __inline void bitmap_intersect(
     IN bitmap4 *dst,
     IN const bitmap4 *src)
-{
-    uint32_t i, count = 0;
-    for (i = 0; i < 3; i++) {
-        dst->arr[i] &= src->arr[i];
-        if (dst->arr[i])
-            count = i+1;
-    }
+{
+    uint32_t i, count = 0;
+    for (i = 0; i < 3; i++) {
+        dst->arr[i] = ((i < dst->count)?dst->arr[i]:0) & ((i < src->count)?src->arr[i]:0);
+        if (dst->arr[i])
+            count = i+1;
+    }
     dst->count = min(dst->count, count);
 }