[ 25/79] ipv6: in case of link failure remove route directly instead of letting it expire

From: Greg Kroah-Hartman
Date: Fri Jul 26 2013 - 17:36:09 EST

3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>

[ Upstream commit 1eb4f758286884e7566627164bca4c4a16952a83 ]

We could end up expiring a route which is part of an ecmp route set. Doing
so would invalidate the rt->rt6i_nsiblings calculations and could provoke
the following panic:

[ 80.144667] ------------[ cut here ]------------
[ 80.145172] kernel BUG at net/ipv6/ip6_fib.c:733!
[ 80.145172] invalid opcode: 0000 [#1] SMP
[ 80.145172] Modules linked in: 8021q nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 iptable_nat nf_nat_ipv4 nf_nat iptable_mangle nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_filter ebtables ip6table_filter ip6_tables
+snd_hda_intel snd_hda_codec snd_hwdep snd_seq snd_seq_device snd_pcm snd_page_alloc snd_timer virtio_balloon snd soundcore i2c_piix4 i2c_core virtio_net virtio_blk
[ 80.145172] CPU: 1 PID: 786 Comm: ping6 Not tainted 3.10.0+ #118
[ 80.145172] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 80.145172] task: ffff880117fa0000 ti: ffff880118770000 task.ti: ffff880118770000
[ 80.145172] RIP: 0010:[<ffffffff815f3b5d>] [<ffffffff815f3b5d>] fib6_add+0x75d/0x830
[ 80.145172] RSP: 0018:ffff880118771798 EFLAGS: 00010202
[ 80.145172] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88011350e480
[ 80.145172] RDX: ffff88011350e238 RSI: 0000000000000004 RDI: ffff88011350f738
[ 80.145172] RBP: ffff880118771848 R08: ffff880117903280 R09: 0000000000000001
[ 80.145172] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88011350f680
[ 80.145172] R13: ffff880117903280 R14: ffff880118771890 R15: ffff88011350ef90
[ 80.145172] FS: 00007f02b5127740(0000) GS:ffff88011fd00000(0000) knlGS:0000000000000000
[ 80.145172] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 80.145172] CR2: 00007f981322a000 CR3: 00000001181b1000 CR4: 00000000000006e0
[ 80.145172] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 80.145172] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 80.145172] Stack:
[ 80.145172] 0000000000000001 ffff880100000000 ffff880100000000 ffff880117903280
[ 80.145172] 0000000000000000 ffff880119a4cf00 0000000000000400 00000000000007fa
[ 80.145172] 0000000000000000 0000000000000000 0000000000000000 ffff88011350f680
[ 80.145172] Call Trace:
[ 80.145172] [<ffffffff815eeceb>] ? rt6_bind_peer+0x4b/0x90
[ 80.145172] [<ffffffff815ed985>] __ip6_ins_rt+0x45/0x70
[ 80.145172] [<ffffffff815eee35>] ip6_ins_rt+0x35/0x40
[ 80.145172] [<ffffffff815ef1e4>] ip6_pol_route.isra.44+0x3a4/0x4b0
[ 80.145172] [<ffffffff815ef34a>] ip6_pol_route_output+0x2a/0x30
[ 80.145172] [<ffffffff81616077>] fib6_rule_action+0xd7/0x210
[ 80.145172] [<ffffffff815ef320>] ? ip6_pol_route_input+0x30/0x30
[ 80.145172] [<ffffffff81553026>] fib_rules_lookup+0xc6/0x140
[ 80.145172] [<ffffffff81616374>] fib6_rule_lookup+0x44/0x80
[ 80.145172] [<ffffffff815ef320>] ? ip6_pol_route_input+0x30/0x30
[ 80.145172] [<ffffffff815edea3>] ip6_route_output+0x73/0xb0
[ 80.145172] [<ffffffff815dfdf3>] ip6_dst_lookup_tail+0x2c3/0x2e0
[ 80.145172] [<ffffffff813007b1>] ? list_del+0x11/0x40
[ 80.145172] [<ffffffff81082a4c>] ? remove_wait_queue+0x3c/0x50
[ 80.145172] [<ffffffff815dfe4d>] ip6_dst_lookup_flow+0x3d/0xa0
[ 80.145172] [<ffffffff815fda77>] rawv6_sendmsg+0x267/0xc20
[ 80.145172] [<ffffffff815a8a83>] inet_sendmsg+0x63/0xb0
[ 80.145172] [<ffffffff8128eb93>] ? selinux_socket_sendmsg+0x23/0x30
[ 80.145172] [<ffffffff815218d6>] sock_sendmsg+0xa6/0xd0
[ 80.145172] [<ffffffff81524a68>] SYSC_sendto+0x128/0x180
[ 80.145172] [<ffffffff8109825c>] ? update_curr+0xec/0x170
[ 80.145172] [<ffffffff81041d09>] ? kvm_clock_get_cycles+0x9/0x10
[ 80.145172] [<ffffffff810afd1e>] ? __getnstimeofday+0x3e/0xd0
[ 80.145172] [<ffffffff8152509e>] SyS_sendto+0xe/0x10
[ 80.145172] [<ffffffff8164efd9>] system_call_fastpath+0x16/0x1b
[ 80.145172] Code: fe ff ff 41 f6 45 2a 06 0f 85 ca fe ff ff 49 8b 7e 08 4c 89 ee e8 94 ef ff ff e9 b9 fe ff ff 48 8b 82 28 05 00 00 e9 01 ff ff ff <0f> 0b 49 8b 54 24 30 0d 00 00 40 00 89 83 14 01 00 00 48 89 53
[ 80.145172] RIP [<ffffffff815f3b5d>] fib6_add+0x75d/0x830
[ 80.145172] RSP <ffff880118771798>
[ 80.387413] ---[ end trace 02f20b7a8b81ed95 ]---
[ 80.390154] Kernel panic - not syncing: Fatal exception in interrupt

Signed-off-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Cc: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Cc: YOSHIFUJI Hideaki <yoshfuji@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/route.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1076,10 +1076,13 @@ static void ip6_link_failure(struct sk_b

rt = (struct rt6_info *) skb_dst(skb);
if (rt) {
- if (rt->rt6i_flags & RTF_CACHE)
- rt6_update_expires(rt, 0);
- else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT))
+ if (rt->rt6i_flags & RTF_CACHE) {
+ dst_hold(&rt->dst);
+ if (ip6_del_rt(rt))
+ dst_free(&rt->dst);
+ } else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT)) {
rt->rt6i_node->fn_sernum = -1;
+ }
}
}



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