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>

1 files changed, 6 insertions, 5 deletions

diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c
index aacba76070fc..e2e2d33cafdf 100644
--- a/net/netrom/nr_route.c
+++ b/net/netrom/nr_route.c
@@ -843,12 +843,13 @@ int nr_route_frame(struct sk_buff *skb, ax25_cb *ax25)
         dptr  = skb_push(skb, 1);
         *dptr = AX25_P_NETROM;
 
-        ax25s = ax25_send_frame(skb, 256, (ax25_address *)dev->dev_addr, &nr_neigh->callsign, nr_neigh->digipeat, nr_neigh->dev);
-        if (nr_neigh->ax25 && ax25s) {
-                /* We were already holding this ax25_cb */
+        ax25s = nr_neigh->ax25;
+        nr_neigh->ax25 = ax25_send_frame(skb, 256,
+                                         (ax25_address *)dev->dev_addr,
+                                         &nr_neigh->callsign,
+                                         nr_neigh->digipeat, nr_neigh->dev);
+        if (ax25s)
                 ax25_cb_put(ax25s);
-        }
-        nr_neigh->ax25 = ax25s;
 
         dev_put(dev);
         ret = (nr_neigh->ax25 != NULL);