diff --git a/src/conf/virinterfaceobj.c b/src/conf/virinterfaceobj.c
index 9470b4a6a3..8bd8094c58 100644
--- a/src/conf/virinterfaceobj.c
+++ b/src/conf/virinterfaceobj.c
@@ -109,11 +109,11 @@ virInterfaceObjListNew(void)
 int
 virInterfaceObjListFindByMACString(virInterfaceObjListPtr interfaces,
                                    const char *mac,
-                                   virInterfaceObjPtr *matches,
+                                   char **const matches,
                                    int maxmatches)
 {
     size_t i;
-    unsigned int matchct = 0;
+    int matchct = 0;
 
     for (i = 0; i < interfaces->count; i++) {
         virInterfaceObjPtr obj = interfaces->objs[i];
@@ -122,18 +122,23 @@ virInterfaceObjListFindByMACString(virInterfaceObjListPtr interfaces,
         virInterfaceObjLock(obj);
         def = obj->def;
         if (STRCASEEQ(def->mac, mac)) {
-            matchct++;
-            if (matchct <= maxmatches) {
-                matches[matchct - 1] = obj;
-                /* keep the lock if we're returning object to caller */
-                /* it is the caller's responsibility to unlock *all* matches */
-                continue;
+            if (matchct < maxmatches) {
+                if (VIR_STRDUP(matches[matchct], def->name) < 0) {
+                    virInterfaceObjUnlock(obj);
+                    goto error;
+                }
+                matchct++;
             }
         }
         virInterfaceObjUnlock(obj);
-
     }
     return matchct;
+
+ error:
+    while (--matchct >= 0)
+        VIR_FREE(matches[matchct]);
+
+    return -1;
 }
 
 
diff --git a/src/conf/virinterfaceobj.h b/src/conf/virinterfaceobj.h
index f1bcab931f..3934e6395e 100644
--- a/src/conf/virinterfaceobj.h
+++ b/src/conf/virinterfaceobj.h
@@ -44,7 +44,7 @@ virInterfaceObjListNew(void);
 int
 virInterfaceObjListFindByMACString(virInterfaceObjListPtr interfaces,
                                    const char *mac,
-                                   virInterfaceObjPtr *matches,
+                                   char **const matches,
                                    int maxmatches);
 
 virInterfaceObjPtr
diff --git a/src/test/test_driver.c b/src/test/test_driver.c
index 8444e91d05..511d65fbe4 100644
--- a/src/test/test_driver.c
+++ b/src/test/test_driver.c
@@ -3728,17 +3728,18 @@ testInterfaceLookupByMACString(virConnectPtr conn,
                                const char *mac)
 {
     testDriverPtr privconn = conn->privateData;
-    virInterfaceObjPtr obj;
-    virInterfaceDefPtr def;
     int ifacect;
+    char *ifacenames[] = { NULL, NULL };
     virInterfacePtr ret = NULL;
 
     testDriverLock(privconn);
-    ifacect = virInterfaceObjListFindByMACString(privconn->ifaces, mac, &obj, 1);
+    ifacect = virInterfaceObjListFindByMACString(privconn->ifaces, mac,
+                                                 ifacenames, 2);
     testDriverUnlock(privconn);
 
     if (ifacect == 0) {
-        virReportError(VIR_ERR_NO_INTERFACE, NULL);
+        virReportError(VIR_ERR_NO_INTERFACE,
+                       _("no interface with matching mac '%s'"), mac);
         goto cleanup;
     }
 
@@ -3747,12 +3748,11 @@ testInterfaceLookupByMACString(virConnectPtr conn,
         goto cleanup;
     }
 
-    def = virInterfaceObjGetDef(obj);
-    ret = virGetInterface(conn, def->name, def->mac);
+    ret = virGetInterface(conn, ifacenames[0], mac);
 
  cleanup:
-    if (obj)
-        virInterfaceObjUnlock(obj);
+    VIR_FREE(ifacenames[0]);
+    VIR_FREE(ifacenames[1]);
     return ret;
 }