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SubjectRe: [3.1] Divide by zero in __tcp_select_window()
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Le lundi 14 novembre 2011 à 15:36 -0500, David Miller a écrit :
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Tue, 08 Nov 2011 22:23:25 +0100
>
> > 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

[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 <sim@hostway.ca>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
---
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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