mac80211: Move call to mpp_path_lookup inside RCU-read section

PROVE_RCU caught that one:

[  431.214070] ===================================================
[  431.215341] [ INFO: suspicious rcu_dereference_check() usage. ]
[  431.215674] ---------------------------------------------------
[  431.216043] net/mac80211/mesh_pathtbl.c:184 invoked
rcu_dereference_check() without protection!

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index e1a39ed..c9f1211 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1751,6 +1751,7 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
                        ret = NETDEV_TX_OK;
                        goto fail;
                }
+               rcu_read_lock();
                if (!is_multicast_ether_addr(skb->data))
                        mppath = mpp_path_lookup(skb->data, sdata);
 
@@ -1765,13 +1766,13 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
                    !(mppath && compare_ether_addr(mppath->mpp, skb->data))) {
                        hdrlen = ieee80211_fill_mesh_addresses(&hdr, &fc,
                                        skb->data, skb->data + ETH_ALEN);
+                       rcu_read_unlock();
                        meshhdrlen = ieee80211_new_mesh_header(&mesh_hdr,
                                        sdata, NULL, NULL);
                } else {
                        int is_mesh_mcast = 1;
                        const u8 *mesh_da;
 
-                       rcu_read_lock();
                        if (is_multicast_ether_addr(skb->data))
                                /* DA TA mSA AE:SA */
                                mesh_da = skb->data;