Upstream commit:
VXLAN device can receive skb with checksum partial. But the checksum
offset could be in outer header which is pulled on receive. This results
in negative checksum offset for the skb. Such skb can cause the assert
failure in skb_checksum_help(). Following patch fixes the bug by setting
checksum-none while pulling outer header.
Following is the kernel panic msg from old kernel hitting the bug.
------------[ cut here ]------------
kernel BUG at net/core/dev.c:1906!
RIP: 0010:[<ffffffff81518034>] skb_checksum_help+0x144/0x150
Call Trace:
<IRQ>
[<ffffffffa0164c28>] queue_userspace_packet+0x408/0x470 [openvswitch]
[<ffffffffa016614d>] ovs_dp_upcall+0x5d/0x60 [openvswitch]
[<ffffffffa0166236>] ovs_dp_process_packet_with_key+0xe6/0x100 [openvswitch]
[<ffffffffa016629b>] ovs_dp_process_received_packet+0x4b/0x80 [openvswitch]
[<ffffffffa016c51a>] ovs_vport_receive+0x2a/0x30 [openvswitch]
[<ffffffffa0171383>] vxlan_rcv+0x53/0x60 [openvswitch]
[<ffffffffa01734cb>] vxlan_udp_encap_recv+0x8b/0xf0 [openvswitch]
[<ffffffff8157addc>] udp_queue_rcv_skb+0x2dc/0x3b0
[<ffffffff8157b56f>] __udp4_lib_rcv+0x1cf/0x6c0
[<ffffffff8157ba7a>] udp_rcv+0x1a/0x20
[<ffffffff8154fdbd>] ip_local_deliver_finish+0xdd/0x280
[<ffffffff81550128>] ip_local_deliver+0x88/0x90
[<ffffffff8154fa7d>] ip_rcv_finish+0x10d/0x370
[<ffffffff81550365>] ip_rcv+0x235/0x300
[<ffffffff8151ba1d>] __netif_receive_skb+0x55d/0x620
[<ffffffff8151c360>] netif_receive_skb+0x80/0x90
[<ffffffff81459935>] virtnet_poll+0x555/0x6f0
[<ffffffff8151cd04>] net_rx_action+0x134/0x290
[<ffffffff810683d8>] __do_softirq+0xa8/0x210
[<ffffffff8162fe6c>] call_softirq+0x1c/0x30
[<ffffffff810161a5>] do_softirq+0x65/0xa0
[<ffffffff810687be>] irq_exit+0x8e/0xb0
[<ffffffff81630733>] do_IRQ+0x63/0xe0
[<ffffffff81625f2e>] common_interrupt+0x6e/0x6e
Reported-by: Anupam Chanda <acha...@vmware.com>
Signed-off-by: Pravin B Shelar <pshe...@nicira.com>
Acked-by: Tom Herbert <t...@herbertland.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Upstream: 6ae459bdaae ("skbuff: Fix skb checksum flag on skb pull")
Signed-off-by: Pravin B Shelar <pshe...@nicira.com>
---
datapath/linux/compat/include/linux/skbuff.h | 24 ++++++++++++++++++++++++
1 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/datapath/linux/compat/include/linux/skbuff.h
b/datapath/linux/compat/include/linux/skbuff.h
index 1a576a0..23b13b8 100644
--- a/datapath/linux/compat/include/linux/skbuff.h
+++ b/datapath/linux/compat/include/linux/skbuff.h
@@ -372,4 +372,28 @@ int rpl_skb_vlan_push(struct sk_buff *skb, __be16
vlan_proto, u16 vlan_tci);
void rpl_kfree_skb_list(struct sk_buff *segs);
#define kfree_skb_list rpl_kfree_skb_list
#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,3,0)
+#define skb_postpull_rcsum rpl_skb_postpull_rcsum
+static inline void skb_postpull_rcsum(struct sk_buff *skb,
+ const void *start, unsigned int len)
+{
+ if (skb->ip_summed == CHECKSUM_COMPLETE)
+ skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
+ else if (skb->ip_summed == CHECKSUM_PARTIAL &&
+ skb_checksum_start_offset(skb) <= len)
+ skb->ip_summed = CHECKSUM_NONE;
+}
+
+#define skb_pull_rcsum rpl_skb_pull_rcsum
+static inline unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int
len)
+{
+ BUG_ON(len > skb->len);
+ skb->len -= len;
+ BUG_ON(skb->len < skb->data_len);
+ skb_postpull_rcsum(skb, skb->data, len);
+ return skb->data += len;
+}
+
+#endif
#endif
--
1.7.1
_______________________________________________
dev mailing list
dev@openvswitch.org
http://openvswitch.org/mailman/listinfo/dev
