diff --git a/zebra/kernel_netlink.c b/zebra/kernel_netlink.c
index fb1015e5d5..058d14481e 100644
--- a/zebra/kernel_netlink.c
+++ b/zebra/kernel_netlink.c
@@ -349,7 +349,7 @@ addattr_l (struct nlmsghdr *n, unsigned int maxlen, int type,
   if (data)
     memcpy (RTA_DATA (rta), data, alen);
   else
-    assert (len == 0);
+    assert (alen == 0);
 
   n->nlmsg_len = NLMSG_ALIGN (n->nlmsg_len) + RTA_ALIGN (len);
 
@@ -375,7 +375,7 @@ rta_addattr_l (struct rtattr *rta, unsigned int maxlen, int type,
   if (data)
     memcpy (RTA_DATA (subrta), data, alen);
   else
-    assert (len == 0);
+    assert (alen == 0);
 
   rta->rta_len = NLMSG_ALIGN (rta->rta_len) + RTA_ALIGN (len);