Thread (8 messages) flat view 8 messages, 3 authors, 2011-11-16

Re: [3.1] Divide by zero in __tcp_select_window()

From: Simon Kirby <hidden>
Date: 2011-11-16 19:54:31
Also in: lkml

On Mon, Nov 14, 2011 at 09:56:56PM +0100, Eric Dumazet wrote:
Le lundi 14 novembre 2011 ?? 15:36 -0500, David Miller a ??crit :
quoted
From: Eric Dumazet <redacted>
Date: Tue, 08 Nov 2011 22:23:25 +0100
quoted
OK, it seems we let a timer running while we free the socket (same error
path than your previous bug report, because of the NULL route)

We arm this keepalive timer in tcp_create_openreq_child()

net/ipv4/tcp_minisocks.c:513
	if (sock_flag(newsk, SOCK_KEEPOPEN))
		inet_csk_reset_keepalive_timer(newsk,
			keepalive_time_when(newtp));

I would try to add a call to tcp_clear_xmit_timers() as well

Please try following patch :
We've been waiting quite some time to get some testing validation on
this patch, but I think it's correct.

Eric can you formally submit this?  Thanks!
Sure, here it is.

Please Simon feel free to add your "Tested-by" signature 

Thanks
Looks good, thanks! Working on ~25 boxes without issue for >36 hours.

Simon-

Tested-by: Simon Kirby <redacted>
quoted hunk ↗ jump to hunk
[PATCH] tcp: clear xmit timers in tcp_v4_syn_recv_sock()

Simon Kirby reported divides by zero errors in __tcp_select_window()

This happens when inet_csk_route_child_sock() returns a NULL pointer :

We free new socket while we eventually armed keepalive timer in
tcp_create_openreq_child()

Fix this by a call to tcp_clear_xmit_timers()

[ This is a followup to commit 918eb39962dff (net: add missing
bh_unlock_sock() calls) ]

Reported-by: Simon Kirby <redacted>
Signed-off-by: Eric Dumazet <redacted>
---
 net/ipv4/tcp_ipv4.c |    1 +
 1 file changed, 1 insertion(+)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a744315..a9db4b1 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1510,6 +1510,7 @@ exit:
 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 	return NULL;
 put_and_exit:
+	tcp_clear_xmit_timers(newsk);
 	bh_unlock_sock(newsk);
 	sock_put(newsk);
 	goto exit;
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