From: Eric Dumazet edumazet@google.com
Since ip6frag_expire_frag_queue() now pulls the head skb from frag queue, we should no longer use skb_get(), since this leads to an skb leak.
Stefan Bader initially reported a problem in 4.4.stable [1] caused by the skb_get(), so this patch should also fix this issue.
296583.091021] kernel BUG at /build/linux-6VmqmP/linux-4.4.0/net/core/skbuff.c:1207! [296583.091734] Call Trace: [296583.091749] [<ffffffff81740e50>] __pskb_pull_tail+0x50/0x350 [296583.091764] [<ffffffff8183939a>] _decode_session6+0x26a/0x400 [296583.091779] [<ffffffff817ec719>] __xfrm_decode_session+0x39/0x50 [296583.091795] [<ffffffff818239d0>] icmpv6_route_lookup+0xf0/0x1c0 [296583.091809] [<ffffffff81824421>] icmp6_send+0x5e1/0x940 [296583.091823] [<ffffffff81753238>] ? __netif_receive_skb+0x18/0x60 [296583.091838] [<ffffffff817532b2>] ? netif_receive_skb_internal+0x32/0xa0 [296583.091858] [<ffffffffc0199f74>] ? ixgbe_clean_rx_irq+0x594/0xac0 [ixgbe] [296583.091876] [<ffffffffc04eb260>] ? nf_ct_net_exit+0x50/0x50 [nf_defrag_ipv6] [296583.091893] [<ffffffff8183d431>] icmpv6_send+0x21/0x30 [296583.091906] [<ffffffff8182b500>] ip6_expire_frag_queue+0xe0/0x120 [296583.091921] [<ffffffffc04eb27f>] nf_ct_frag6_expire+0x1f/0x30 [nf_defrag_ipv6] [296583.091938] [<ffffffff810f3b57>] call_timer_fn+0x37/0x140 [296583.091951] [<ffffffffc04eb260>] ? nf_ct_net_exit+0x50/0x50 [nf_defrag_ipv6] [296583.091968] [<ffffffff810f5464>] run_timer_softirq+0x234/0x330 [296583.091982] [<ffffffff8108a339>] __do_softirq+0x109/0x2b0
Fixes: d4289fcc9b16 ("net: IP6 defrag: use rbtrees for IPv6 defrag") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: Stefan Bader stefan.bader@canonical.com Cc: Peter Oskolkov posk@google.com Cc: Florian Westphal fw@strlen.de Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Baolin Wang baolin.wang@linaro.org --- include/net/ipv6_frag.h | 1 - 1 file changed, 1 deletion(-)
diff --git a/include/net/ipv6_frag.h b/include/net/ipv6_frag.h index 28aa9b3..1f77fb4 100644 --- a/include/net/ipv6_frag.h +++ b/include/net/ipv6_frag.h @@ -94,7 +94,6 @@ static inline u32 ip6frag_obj_hashfn(const void *data, u32 len, u32 seed) goto out;
head->dev = dev; - skb_get(head); spin_unlock(&fq->q.lock);
icmpv6_send(head, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);