[PATCH] Missing initialization of /proc/net/tcp seq_file

We need to initialize st->state in tcp_seq_start().  Otherwise
tcp_seq_stop() is run with previous st->state, and it calls the unneeded
unlock etc, causing a kernel crash.

net/ipv4/tcp_ipv4.c

@@ -2356,6 +2356,7 @@ static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
 {
 	struct tcp_iter_state* st = seq->private;
+	st->state = TCP_SEQ_STATE_LISTENING;
 	st->num = 0;
 	return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 }