batman-adv: fix reference counting imbalance while sending fragment

In the new fragmentation code the batadv_frag_send_packet()
function obtains a reference to the primary_if, but it does
not release it upon return.

This reference imbalance prevents the primary_if (and then
the related netdevice) to be properly released on shut down.

Fix this by releasing the primary_if in batadv_frag_send_packet().

Introduced by ee75ed88879af88558818a5c6609d85f60ff0df4
("batman-adv: Fragment and send skbs larger than mtu")

Cc: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Acked-by: Martin Hundebøll <martin@hundeboll.net>

1 files changed, 8 insertions, 3 deletions

diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index bcc4bea632fa..f14e54a05691 100644
--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -418,12 +418,13 @@ bool batadv_frag_send_packet(struct sk_buff *skb,
                              struct batadv_neigh_node *neigh_node)
 {
         struct batadv_priv *bat_priv;
-        struct batadv_hard_iface *primary_if;
+        struct batadv_hard_iface *primary_if = NULL;
         struct batadv_frag_packet frag_header;
         struct sk_buff *skb_fragment;
         unsigned mtu = neigh_node->if_incoming->net_dev->mtu;
         unsigned header_size = sizeof(frag_header);
         unsigned max_fragment_size, max_packet_size;
+        bool ret = false;
 
         /* To avoid merge and refragmentation at next-hops we never send
          * fragments larger than BATADV_FRAG_MAX_FRAG_SIZE
@@ -483,7 +484,11 @@ bool batadv_frag_send_packet(struct sk_buff *skb,
                            skb->len + ETH_HLEN);
         batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 
-        return true;
+        ret = true;
+
 out_err:
-        return false;
+        if (primary_if)
+                batadv_hardif_free_ref(primary_if);
+
+        return ret;
 }