diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 2f8f93da5dc2660f4db37c04f8a434809b3120a1..9a5ccf03a59b1e0a4820e2a978c66f1df8a9a82f 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -966,7 +966,7 @@ void sctp_transport_burst_limited(struct sctp_transport *);
 void sctp_transport_burst_reset(struct sctp_transport *);
 unsigned long sctp_transport_timeout(struct sctp_transport *);
 void sctp_transport_reset(struct sctp_transport *t);
-void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
+bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
 void sctp_transport_immediate_rtx(struct sctp_transport *);
 void sctp_transport_dst_release(struct sctp_transport *t);
 void sctp_transport_dst_confirm(struct sctp_transport *t);
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 9320661cc41da0b280f69f379128ab7d062e5528..141c9c466ec172ff67930cf38eb02a49e01a12ab 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -406,8 +406,12 @@ void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
 		 */
 		return;
 
-	/* Update transports view of the MTU */
-	sctp_transport_update_pmtu(t, pmtu);
+	/* Update transports view of the MTU. Return if no update was needed.
+	 * If an update wasn't needed/possible, it also doesn't make sense to
+	 * try to retransmit now.
+	 */
+	if (!sctp_transport_update_pmtu(t, pmtu))
+		return;
 
 	/* Update association pmtu. */
 	sctp_assoc_sync_pmtu(asoc);
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 1e5a22430cf56e40a6f323081beb97836b506384..47f82bd794d915188bad037463c2aa14175a55ef 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -248,28 +248,37 @@ void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk)
 		transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
 }
 
-void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)
+bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)
 {
 	struct dst_entry *dst = sctp_transport_dst_check(t);
+	bool change = true;
 
 	if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {
-		pr_warn("%s: Reported pmtu %d too low, using default minimum of %d\n",
-			__func__, pmtu, SCTP_DEFAULT_MINSEGMENT);
-		/* Use default minimum segment size and disable
-		 * pmtu discovery on this transport.
-		 */
-		t->pathmtu = SCTP_DEFAULT_MINSEGMENT;
-	} else {
-		t->pathmtu = pmtu;
+		pr_warn_ratelimited("%s: Reported pmtu %d too low, using default minimum of %d\n",
+				    __func__, pmtu, SCTP_DEFAULT_MINSEGMENT);
+		/* Use default minimum segment instead */
+		pmtu = SCTP_DEFAULT_MINSEGMENT;
 	}
+	pmtu = SCTP_TRUNC4(pmtu);
 
 	if (dst) {
 		dst->ops->update_pmtu(dst, t->asoc->base.sk, NULL, pmtu);
 		dst = sctp_transport_dst_check(t);
 	}
 
-	if (!dst)
+	if (!dst) {
 		t->af_specific->get_dst(t, &t->saddr, &t->fl, t->asoc->base.sk);
+		dst = t->dst;
+	}
+
+	if (dst) {
+		/* Re-fetch, as under layers may have a higher minimum size */
+		pmtu = SCTP_TRUNC4(dst_mtu(dst));
+		change = t->pathmtu != pmtu;
+	}
+	t->pathmtu = pmtu;
+
+	return change;
 }
 
 /* Caches the dst entry and source address for a transport's destination