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

Signed-off-by: Eric Dumazet <edumazet@google.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 <redacted>
Signed-off-by: Eric Dumazet <edumazet@google.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);