ax25: netrom: rose: Fix timer oopses

Wrong ax25_cb refcounting in ax25_send_frame() and by its callers can
cause timer oopses (first reported with 2.6.29.6 kernel).

Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=14905

Reported-by: Bernard Pidoux <bpidoux@free.fr>
Tested-by: Bernard Pidoux <bpidoux@free.fr>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ax25/ax25_out.c b/net/ax25/ax25_out.c
index bf706f8..1491260 100644
--- a/net/ax25/ax25_out.c
+++ b/net/ax25/ax25_out.c
@@ -92,6 +92,12 @@
 #endif
 	}
 
+	/*
+	 * There is one ref for the state machine; a caller needs
+	 * one more to put it back, just like with the existing one.
+	 */
+	ax25_cb_hold(ax25);
+
 	ax25_cb_add(ax25);
 
 	ax25->state = AX25_STATE_1;