From f5990207026987a353d5a95204c4d9cb725637fd Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Fri, 20 Jun 2025 11:48:55 -0700 Subject: [PATCH] net: netpoll: Initialize UDP checksum field before checksumming commit f1fce08e63fe ("netpoll: Eliminate redundant assignment") removed the initialization of the UDP checksum, which was wrong and broke netpoll IPv6 transmission due to bad checksumming. udph->check needs to be set before calling csum_ipv6_magic(). Fixes: f1fce08e63fe ("netpoll: Eliminate redundant assignment") Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250620-netpoll_fix-v1-1-f9f0b82bc059@debian.org Signed-off-by: Jakub Kicinski --- net/core/netpoll.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 4ddb7490df4b..6ad84d4a2b46 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -432,6 +432,7 @@ int netpoll_send_udp(struct netpoll *np, const char *msg, int len) udph->dest = htons(np->remote_port); udph->len = htons(udp_len); + udph->check = 0; if (np->ipv6) { udph->check = csum_ipv6_magic(&np->local_ip.in6, &np->remote_ip.in6, @@ -460,7 +461,6 @@ int netpoll_send_udp(struct netpoll *np, const char *msg, int len) skb_reset_mac_header(skb); skb->protocol = eth->h_proto = htons(ETH_P_IPV6); } else { - udph->check = 0; udph->check = csum_tcpudp_magic(np->local_ip.ip, np->remote_ip.ip, udp_len, IPPROTO_UDP, -- 2.25.1