ip6_append_data is used by other protocols and some of them can't
be partially checksummed.  Only partially checksum UDP protocol.

Fixes: 32dce968dd987a (ipv6: Allow for partial checksums on non-ufo packets)
Reported-by: Sabrian Dubroca <sd@queasysnail.net>
Signed-off-by: Vladislav Yasevich <redacted>
---
Hi Sabrina

Can you try this patch.  Thanks.

 net/ipv6/ip6_output.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index d33df4c..8f2d558 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c

@@ -1273,7 +1273,7 @@ emsgsize:
 	/* If this is the first and only packet and device
 	 * supports checksum offloading, let's use it.
 	 */
-	if (!skb &&
+	if (!skb && sk->protocol == IPPROTO_UDP &&
 	    length + fragheaderlen < mtu &&
 	    rt->dst.dev->features & NETIF_F_V6_CSUM &&
 	    !exthdrlen)

-- 
1.9.3