Patch "vlan: Fix tcp checksum offloads in Q-in-Q vlans" has been added to the 4.11-stable tree
Subsystems (2)
This is a note to let you know that I've just added the patch titled
vlan: Fix tcp checksum offloads in Q-in-Q vlans
to the 4.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vlan-fix-tcp-checksum-offloads-in-q-in-q-vlans.patch
and it can be found in the queue-4.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From foo@baz Wed May 31 09:13:10 JST 2017
From: Vlad Yasevich <[email protected]>
Date: Tue, 23 May 2017 13:38:41 -0400
Subject: vlan: Fix tcp checksum offloads in Q-in-Q vlans
From: Vlad Yasevich <[email protected]>
[ Upstream commit 35d2f80b07bbe03fb358afb0bdeff7437a7d67ff ]
It appears that TCP checksum offloading has been broken for Q-in-Q vlans. The behavior was execerbated by the series
commit afb0bc972b52 ("Merge branch 'stacked_vlan_tso'")that that enabled accleleration features on stacked vlans.
However, event without that series, it is possible to trigger this issue. It just requires a lot more specialized configuration.
The root cause is the interaction between how netdev_intersect_features() works, the features actually set on the vlan devices and HW having the ability to run checksum with longer headers.
The issue starts when netdev_interesect_features() replaces NETIF_F_HW_CSUM with a combination of NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM, if the HW advertises IP|IPV6 specific checksums. This happens
for tagged and multi-tagged packets. However, HW that enables
IP|IPV6 checksum offloading doesn't gurantee that packets with arbitrarily long headers can be checksummed.
This patch disables IP|IPV6 checksums on the packet for multi-tagged packets.
--- include/linux/if_vlan.h | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)
include/linux/if_vlan.h +10 -8
@@ -614,14 +614,16 @@ static inline bool skb_vlan_tagged_multistatic inline netdev_features_t vlan_features_check (const struct sk_buff *skb,netdev_features_t features) { -if (skb_vlan_tagged_multi (skb)) - features =netdev_intersect_features (features, -NETIF_F_SG | -NETIF_F_HIGHDMA | -NETIF_F_FRAGLIST | -NETIF_F_HW_CSUM | -NETIF_F_HW_VLAN_CTAG_TX | -NETIF_F_HW_VLAN_STAG_TX ); +if (skb_vlan_tagged_multi (skb)) { +/* In the case of multi-tagged packets, use a direct mask +* instead of using netdev_interesect_features(), to make +* sure that only devices supporting NETIF_F_HW_CSUM will +* have checksum offloading support. +*/ + features &=NETIF_F_SG |NETIF_F_HIGHDMA |NETIF_F_HW_CSUM | +NETIF_F_FRAGLIST |NETIF_F_HW_VLAN_CTAG_TX | +NETIF_F_HW_VLAN_STAG_TX ; + }return features; }
Patches currently in stable-queue which might be from [email protected] are
queue-4.11/vlan-fix-tcp-checksum-offloads-in-q-in-q-vlans.patch queue-4.11/be2net-fix-offload-features-for-q-in-q-packets.patch queue-4.11/virtio-net-enable-tso-checksum-offloads-for-q-in-q-vlans.patch queue-4.11/sctp-fix-icmp-processing-if-skb-is-non-linear.patch