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Message-ID: <1352331754.2748.14.camel@edumazet-glaptop>
Date: Wed, 07 Nov 2012 15:42:34 -0800
From: Eric Dumazet <eric.dumazet@...il.com>
To: Julius Werner <jwerner@...omium.org>
Cc: linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
Patrick McHardy <kaber@...sh.net>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
James Morris <jmorris@...ei.org>,
Alexey Kuznetsov <kuznet@....inr.ac.ru>,
"David S. Miller" <davem@...emloft.net>,
Dave Jones <davej@...hat.com>,
Sameer Nanda <snanda@...omium.org>,
Mandeep Singh Baines <msb@...omium.org>
Subject: Re: [PATCH] tcp: Avoid infinite loop on recvmsg bug
On Wed, 2012-11-07 at 15:33 -0800, Eric Dumazet wrote:
> So you probably are fighting a bug we already fixed in upstream kernel.
>
> (commit c8628155ece363 "tcp: reduce out_of_order memory use" did not
> played well with cloned skbs.)
>
> This issue was already discussed on netdev in the past.
If you use a 3.4 kernel, you want the following patch.
(I guess you could reproduce the crash easily running a tcpdump in //)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 257b617..9f8f68c 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4496,7 +4496,9 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
* to avoid future tcp_collapse_ofo_queue(),
* probably the most expensive function in tcp stack.
*/
- if (skb->len <= skb_tailroom(skb1) && !tcp_hdr(skb)->fin) {
+ if (skb->len <= skb_tailroom(skb1) &&
+ !tcp_hdr(skb)->fin &&
+ !skb_cloned(skb1)) {
NET_INC_STATS_BH(sock_net(sk),
LINUX_MIB_TCPRCVCOALESCE);
BUG_ON(skb_copy_bits(skb, 0,
--
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