diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index c474e4b4c4bb..fbad7828568f 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1321,8 +1321,8 @@ static int __ip6_append_data(struct sock *sk,
 		      sizeof(struct frag_hdr) : 0) +
 		     rt->rt6i_nfheader_len;
 
-	if (mtu < fragheaderlen ||
-	    ((mtu - fragheaderlen) & ~7) + fragheaderlen < sizeof(struct frag_hdr))
+	if (mtu <= fragheaderlen ||
+	    ((mtu - fragheaderlen) & ~7) + fragheaderlen <= sizeof(struct frag_hdr))
 		goto emsgsize;
 
 	maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -