1 files changed, 3 insertions, 1 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index c21777565c58..bc09cb97b840 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1300,8 +1300,10 @@ emsgsize:
 
         /* If this is the first and only packet and device
          * supports checksum offloading, let's use it.
+         * Use transhdrlen, same as IPv4, because partial
+         * sums only work when transhdrlen is set.
          */
-        if (!skb && sk->sk_protocol == IPPROTO_UDP &&
+        if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
             length + fragheaderlen < mtu &&
             rt->dst.dev->features & NETIF_F_V6_CSUM &&
             !exthdrlen)