netdev - Re: kernel BUG at kernel/timer.c:748!

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Date:	Mon, 24 Sep 2012 19:00:11 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Dave Jones <davej@...hat.com>
Cc:	Yuchung Cheng <ycheng@...gle.com>, Julian Anastasov <ja@....bg>,
	netdev@...r.kernel.org
Subject: Re: kernel BUG at kernel/timer.c:748!

Signed-off-by: Eric Dumazet <edumazet@...gle.com>

On Mon, 2012-09-24 at 18:34 +0200, Eric Dumazet wrote:

> OK, I believe I found the reason. I Will post a patch.
> 
> open a raw socket AF_INET, TCP_PROTO
> + connect() ->sk_state set to TCP_ESTABLISHED
> + setsockopt( SO_KEEPALIVE, &on)  -> crash

I confirm following patch fixes the problem for me.

Thanks again

[PATCH] net: guard tcp_set_keepalive() to tcp sockets

Its possible to use RAW sockets to get a crash in 
tcp_set_keepalive() / sk_reset_timer()

Fix is to make sure socket is a SOCK_STREAM one.

Reported-by: Dave Jones <davej@...hat.com>
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/core/sock.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index 3057920..a6000fb 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -691,7 +691,8 @@ set_rcvbuf:
 
 	case SO_KEEPALIVE:
 #ifdef CONFIG_INET
-		if (sk->sk_protocol == IPPROTO_TCP)
+		if (sk->sk_protocol == IPPROTO_TCP &&
+		    sk->sk_type == SOCK_STREAM)
 			tcp_set_keepalive(sk, valbool);
 #endif
 		sock_valbool_flag(sk, SOCK_KEEPOPEN, valbool);


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