diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index dae1949019d7..be7589ef5cf9 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1093,11 +1093,12 @@ static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
 	return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
 }
 
-static void ip6_append_data_mtu(int *mtu,
+static void ip6_append_data_mtu(unsigned int *mtu,
 				int *maxfraglen,
 				unsigned int fragheaderlen,
 				struct sk_buff *skb,
-				struct rt6_info *rt)
+				struct rt6_info *rt,
+				bool pmtuprobe)
 {
 	if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
 		if (skb == NULL) {
@@ -1109,7 +1110,9 @@ static void ip6_append_data_mtu(int *mtu,
 			 * this fragment is not first, the headers
 			 * space is regarded as data space.
 			 */
-			*mtu = dst_mtu(rt->dst.path);
+			*mtu = min(*mtu, pmtuprobe ?
+				   rt->dst.dev->mtu :
+				   dst_mtu(rt->dst.path));
 		}
 		*maxfraglen = ((*mtu - fragheaderlen) & ~7)
 			      + fragheaderlen - sizeof(struct frag_hdr);
@@ -1126,11 +1129,10 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct inet_cork *cork;
 	struct sk_buff *skb, *skb_prev = NULL;
-	unsigned int maxfraglen, fragheaderlen;
+	unsigned int maxfraglen, fragheaderlen, mtu;
 	int exthdrlen;
 	int dst_exthdrlen;
 	int hh_len;
-	int mtu;
 	int copy;
 	int err;
 	int offset = 0;
@@ -1287,7 +1289,9 @@ alloc_new_skb:
 			/* update mtu and maxfraglen if necessary */
 			if (skb == NULL || skb_prev == NULL)
 				ip6_append_data_mtu(&mtu, &maxfraglen,
-						    fragheaderlen, skb, rt);
+						    fragheaderlen, skb, rt,
+						    np->pmtudisc ==
+						    IPV6_PMTUDISC_PROBE);
 
 			skb_prev = skb;