From ef3db4a5954281bc1ea49a4739c88eaea091dc71 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Wed, 21 Jul 2010 04:32:45 +0000
Subject: [PATCH] tun: avoid BUG, dump packet on GSO errors

There are still some LRO cards that cause GSO errors in tun,
and BUG on this is an unfriendly way to tell the admin
to disable LRO.

Further, experience shows we might have more GSO bugs lurking.
See https://bugzilla.kernel.org/show_bug.cgi?id=16413
as a recent example.
dumping a packet will make it easier to figure it out.

Replace BUG with warning+dump+drop the packet to make
GSO errors in tun less critical and easier to debug.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Alex Unigovsky <unik@compot.ru>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/tun.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 6ad6fe706312f..63042596f0cf3 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -736,8 +736,18 @@ static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 				gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 			else if (sinfo->gso_type & SKB_GSO_UDP)
 				gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
-			else
-				BUG();
+			else {
+				printk(KERN_ERR "tun: unexpected GSO type: "
+				       "0x%x, gso_size %d, hdr_len %d\n",
+				       sinfo->gso_type, gso.gso_size,
+				       gso.hdr_len);
+				print_hex_dump(KERN_ERR, "tun: ",
+					       DUMP_PREFIX_NONE,
+					       16, 1, skb->head,
+					       min((int)gso.hdr_len, 64), true);
+				WARN_ON_ONCE(1);
+				return -EINVAL;
+			}
 			if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 				gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 		} else
-- 
GitLab