netdev - Re: 4.9.2 panic, __skb_flow

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Date:   Wed, 11 Jan 2017 01:49:34 +0200
From:   Denys Fedoryshchenko <nuclearcat@...learcat.com>
To:     Linux Kernel Network Developers <netdev@...r.kernel.org>
Cc:     Ian Kumlien <ian.kumlien@...il.com>
Subject: Re: 4.9.2 panic, __skb_flow_dissect, gro?

It seems this patch solve issue. I hope it will go to stable asap, 
because without it loaded routers crashing almost instantly on 4.9.

commit	d0af683407a26a4437d8fa6e283ea201f2ae8146 (patch)
tree	e769779cf59b0b73333b50a68db5d0b8897a7cb6 /net/core/flow_dissector.c
parent	94ba998b63c41e92da1b2f0cd8679e038181ef48 (diff)
flow_dissector: Update pptp handling to avoid null pointer deref.
__skb_flow_dissect can be called with a skb or a data packet, either
can be NULL. All calls seems to have been moved to __skb_header_pointer
except the pptp handling which is still calling skb_header_pointer.

On 2017-01-11 01:26, Denys Fedoryshchenko wrote:
> Hi,
> 
> Got panic message on 4.9.2 with latest patches from stable-queue,
> probably it affects all 4.9 version
> 
> Panic message:
> 
> dmesg-erst-6374119981415661569:<6>[   23.110324] ip_set: protocol 6
> dmesg-erst-6374119981415661569:<1>[   28.117455] BUG: unable to handle
> kernel NULL pointer dereference at 0000000000000078
> dmesg-erst-6374119981415661569:<1>[   28.118036] IP:
> [<ffffffff8188f9de>] __skb_flow_dissect+0x73f/0x931
> dmesg-erst-6374119981415661569:<4>[   28.118360] PGD 0
> dmesg-erst-6374119981415661569:<4>[   28.118427]
> dmesg-erst-6374119981415661569:<4>[   28.118730] Oops: 0000 [#1] SMP
> dmesg-erst-6374119981415661569:<4>[   28.118977] Modules linked in:
> xt_TCPMSS xt_connmark ipt_MASQUERADE nf_nat_masquerade_ipv4 xt_nat
> xt_rateest xt_RATEEST nf_conntrack_pptp nf_conntrack_proto_gre xt_CT
> xt_set xt_hl xt_tcpudp ip_set_hash_net ip_set nfnetlink iptable_raw
> iptable_mangle iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4
> nf_nat_ipv4 nf_nat nf_conntrack iptable_filter ip_tables x_tables
> 8021q garp mrp stp llc netconsole configfs bonding ixgbe dca
> ipmi_watchdog ipmi_si acpi_ipmi ipmi_msghandler
> dmesg-erst-6374119981415661569:<4>[   28.122784] CPU: 4 PID: 0 Comm:
> swapper/4 Not tainted 4.9.2-build-0127 #3
> dmesg-erst-6374119981415661569:<4>[   28.123042] Hardware name: Intel
> Corporation S2600WTT/S2600WTT, BIOS
> SE5C610.86B.01.01.0019.101220160604 10/12/2016
> dmesg-erst-6374119981415661569:<4>[   28.123488] task:
> ffff882fa6af24c0 task.stack: ffffc90031338000
> dmesg-erst-6374119981415661569:<4>[   28.123742] RIP:
> 0010:[<ffffffff8188f9de>]  [<ffffffff8188f9de>]
> __skb_flow_dissect+0x73f/0x931
> dmesg-erst-6374119981415661569:<4>[   28.124243] RSP:
> 0018:ffff882fbfb03ce8  EFLAGS: 00010206
> dmesg-erst-6374119981415661569:<4>[   28.124497] RAX: 0000000000000130
> RBX: 0000000000000022 RCX: ffff882f9eabb000
> dmesg-erst-6374119981415661569:<4>[   28.124756] RDX: 0000000000000010
> RSI: ffff882f9eabb026 RDI: 000000000000002f
> dmesg-erst-6374119981415661569:<4>[   28.125015] RBP: ffff882fbfb03d78
> R08: 000000000000000c R09: ffff882f9eabb022
> dmesg-erst-6374119981415661569:<4>[   28.125275] R10: 0000000000000140
> R11: 0000000000000001 R12: 0000000000000b88
> dmesg-erst-6374119981415661569:<4>[   28.125532] R13: ffff882fbfb03d9c
> R14: 0000000000000000 R15: ffffffff820c11a0
> dmesg-erst-6374119981415661569:<4>[   28.125792] FS:
> 0000000000000000(0000) GS:ffff882fbfb00000(0000)
> knlGS:0000000000000000
> dmesg-erst-6374119981415661569:<4>[   28.126227] CS:  0010 DS: 0000
> ES: 0000 CR0: 0000000080050033
> dmesg-erst-6374119981415661569:<4>[   28.126482] CR2: 0000000000000078
> CR3: 000000607f007000 CR4: 00000000001406e0
> dmesg-erst-6374119981415661569:<4>[   28.126741] Stack:
> dmesg-erst-6374119981415661569:<4>[   28.126983]  ffff882fbfb03cf8
> ffffffff81885afb 00000001bfb03d88 ffffffff818953b5
> dmesg-erst-6374119981415661569:<4>[   28.127675]  ffff882fbfb03d9c
> 2f00000800000000 ffff882f9eabb000 ffff882fbfb03d48
> dmesg-erst-6374119981415661569:<4>[   28.128350]  ffffffff818ef3e4
> ffff882fa4177400 000000000000004e 0000000000000000
> dmesg-erst-6374119981415661569:<4>[   28.129027] Call Trace:
> dmesg-erst-6374119981415661569:<4>[   28.129271]  <IRQ>
> dmesg-erst-6374119981415661569:<4>[   28.129340]  [<ffffffff81885afb>]
> ? kfree_skb+0x25/0x27
> dmesg-erst-6374119981415661569:<4>[   28.129655]  [<ffffffff818953b5>]
> ? __netif_receive_skb_core+0x61b/0x807
> dmesg-erst-6374119981415661569:<4>[   28.129917]  [<ffffffff818ef3e4>]
> ? udp4_gro_receive+0x1f6/0x256
> dmesg-erst-6374119981415661569:<4>[   28.130174]  [<ffffffff818b43d3>]
> eth_get_headlen+0x4c/0x82
> dmesg-erst-6374119981415661569:<4>[   28.130435]  [<ffffffffa003624f>]
> ixgbe_clean_rx_irq+0x546/0x924 [ixgbe]
> dmesg-erst-6374119981415661569:<4>[   28.130694]  [<ffffffffa003723a>]
> ixgbe_poll+0x4ef/0x679 [ixgbe]
> dmesg-erst-6374119981415661569:<4>[   28.130952]  [<ffffffff81896b60>]
> net_rx_action+0x107/0x27d
> dmesg-erst-6374119981415661569:<4>[   28.131207]  [<ffffffff810d18c8>]
> __do_softirq+0xb5/0x1a3
> dmesg-erst-6374119981415661569:<4>[   28.131460]  [<ffffffff810d1b2d>]
> irq_exit+0x4d/0x8e
> dmesg-erst-6374119981415661569:<4>[   28.131712]  [<ffffffff81016bb7>]
> do_IRQ+0xaa/0xc2
> dmesg-erst-6374119981415661569:<4>[   28.131965]  [<ffffffff8191483c>]
> common_interrupt+0x7c/0x7c
> dmesg-erst-6374119981415661569:<4>[   28.132217]  <EOI>
> dmesg-erst-6374119981415661569:<4>[   28.132286]  [<ffffffff81913936>]
> ? mwait_idle+0x4e/0x61
> dmesg-erst-6374119981415661569:<4>[   28.132773]  [<ffffffff8101cb40>]
> arch_cpu_idle+0xa/0xc
> dmesg-erst-6374119981415661569:<4>[   28.133026]  [<ffffffff81913a4b>]
> default_idle_call+0x20/0x22
> dmesg-erst-6374119981415661569:<4>[   28.133282]  [<ffffffff810fa1a5>]
> cpu_startup_entry+0xde/0x185
> dmesg-erst-6374119981415661569:<4>[   28.133539]  [<ffffffff8102bda3>]
> start_secondary+0xe8/0xeb
> dmesg-erst-6374119981415661569:<4>[   28.133792] Code: f7 e8 eb 63 ff
> ff 85 c0 0f 88 d5 01 00 00 44 8b 45 80 48 8d 75 b0 66 44 8b 66 0c 41
> 83 c0 0e e9 87 00 00 00 41 8d 50 04 66 85 c0 <41> 8b 46 78 44 0f 48 c2
> 41 2b 46 7c 42 8d 34 03 29 f0 83 f8 03
> dmesg-erst-6374119981415661569:<1>[   28.138401] RIP
> [<ffffffff8188f9de>] __skb_flow_dissect+0x73f/0x931
> dmesg-erst-6374119981415661569:<4>[   28.138718]  RSP 
> <ffff882fbfb03ce8>
> dmesg-erst-6374119981415661569:<4>[   28.138964] CR2: 0000000000000078
> dmesg-erst-6374119981415661569:<4>[   28.139215] ---[ end trace
> 46fb1cf5af272d67 ]---