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authorPavel Emelyanov <xemul@openvz.org>2008-04-23 11:47:15 +0400
committerJohn W. Linville <linville@tuxdriver.com>2008-04-23 21:25:35 -0400
commit1ebebea8e844d01c80b93b8ee4d696ee7c0cbc27 (patch)
tree9e246a1aa36afcd735940a07253124b138e0ed03
parentd1d8f44a4e3c730984283c0bf4b3458e3a88c15a (diff)
mac80211: Fix race between ieee80211_rx_bss_put and lookup routines.
The put routine first decrements the users counter and then (if it is zero) locks the sta_bss_lock and removes one from the list and the hash. Thus, any of ieee80211_sta_config_auth, ieee80211_rx_bss_get or ieee80211_rx_mesh_bss_get can race with it by finding a bss that is about to get kfree-ed. Using atomic_dec_and_lock in ieee80211_rx_bss_put takes care of this race. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
-rw-r--r--net/mac80211/mlme.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index c0a5345c8a6..a5e5c31c23a 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2248,10 +2248,13 @@ static void ieee80211_rx_bss_put(struct net_device *dev,
struct ieee80211_sta_bss *bss)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
- if (!atomic_dec_and_test(&bss->users))
+
+ local_bh_disable();
+ if (!atomic_dec_and_lock(&bss->users, &local->sta_bss_lock)) {
+ local_bh_enable();
return;
+ }
- spin_lock_bh(&local->sta_bss_lock);
__ieee80211_rx_bss_hash_del(dev, bss);
list_del(&bss->list);
spin_unlock_bh(&local->sta_bss_lock);