Re: [PATCH] ip_gre: fix kernel panic with icmp_dest_unreach

[Eric Dumazet <eric.dumazet@gmail.com>]

On Thu, 2013-05-23 at 08:53 -0700, Eric Dumazet wrote:
> On Thu, 2013-05-23 at 11:47 +0300, Daniel Petre wrote:
> 
> > 
> > Hello again Eric,
> > we applied the little patch from:
> > http://lkml.indiana.edu/hypermail/linux/kernel/1007.0/00961.html
> > we have flapped the link few times and everything recovered smooth.
> > 
> 
> Thats a very good catch, now we have to fix the bug at the right place.


Please try the following patch :

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 91d66db..563358e 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -795,6 +795,7 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
 
 	if (dev->type == ARPHRD_ETHER)
 		IPCB(skb)->flags = 0;
+	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 
 	if (dev->header_ops && dev->type == ARPHRD_IPGRE) {
 		gre_hlen = 0;
@@ -952,7 +953,6 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
 	skb_push(skb, gre_hlen);
 	skb_reset_network_header(skb);
 	skb_set_transport_header(skb, sizeof(*iph));
-	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
 			      IPSKB_REROUTED);
 	skb_dst_drop(skb);