lkml.org 
[lkml]   [2012]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: [PATCH] tcp: Avoid infinite loop on recvmsg bug
From
Date
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,




\
 
 \ /
  Last update: 2012-11-08 01:24    [W:0.063 / U:0.132 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site