This is a note to let you know that I've just added the patch titled skbuff: Fix skb checksum flag on skb pull to the 4.2-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: skbuff-fix-skb-checksum-flag-on-skb-pull.patch and it can be found in the queue-4.2 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Oct 22 17:25:24 PDT 2015 From: Pravin B Shelar <pshelar@xxxxxxxxxx> Date: Tue, 22 Sep 2015 12:57:53 -0700 Subject: skbuff: Fix skb checksum flag on skb pull From: Pravin B Shelar <pshelar@xxxxxxxxxx> [ Upstream commit 6ae459bdaaeebc632b16e54dcbabb490c6931d61 ] 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 <achanda@xxxxxxxxxx> Signed-off-by: Pravin B Shelar <pshelar@xxxxxxxxxx> Acked-by: Tom Herbert <tom@xxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- include/linux/skbuff.h | 3 +++ 1 file changed, 3 insertions(+) --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2601,6 +2601,9 @@ static inline void skb_postpull_rcsum(st { 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; } unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len); Patches currently in stable-queue which might be from pshelar@xxxxxxxxxx are queue-4.2/ovs-do-not-allocate-memory-from-offline-numa-node.patch queue-4.2/skbuff-fix-skb-checksum-flag-on-skb-pull.patch queue-4.2/skbuff-fix-skb-checksum-partial-check.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html