From 5465740ace36f179de5bb0ccb5d46ddeb945e309 Mon Sep 17 00:00:00 2001 From: Pravin B Shelar Date: Wed, 23 Jan 2013 11:45:42 +0000 Subject: [PATCH] IP_GRE: Fix kernel panic in IP_GRE with GRE csum. Due to IP_GRE GSO support, GRE can recieve non linear skb which results in panic in case of GRE_CSUM. Following patch fixes it by using correct csum API. Bug introduced in commit 6b78f16e4bdde3936b (gre: add GSO support) Signed-off-by: Pravin B Shelar Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/ip_gre.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 303012adf9e..e81b1caf2ea 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -963,8 +963,12 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev ptr--; } if (tunnel->parms.o_flags&GRE_CSUM) { + int offset = skb_transport_offset(skb); + *ptr = 0; - *(__sum16 *)ptr = ip_compute_csum((void *)(iph+1), skb->len - sizeof(struct iphdr)); + *(__sum16 *)ptr = csum_fold(skb_checksum(skb, offset, + skb->len - offset, + 0)); } }