mac80211: avoid crashing when no scan sdata

Using the scan_sdata variable here is terribly wrong,
if there has never been a scan then we fail. However,
we need a bandaid...

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: stable@kernel.org [2.6.29]
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 1b14d0204dd29169c5fdef7eb77dc1a44d380cc3..dc60804d6dd0309aa376e000203bfe74e46d55d1 100644 (file)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2113,12 +2113,13 @@ void ieee80211_dynamic_ps_enable_work(struct work_struct *work)
        struct ieee80211_local *local =
                container_of(work, struct ieee80211_local,
                             dynamic_ps_enable_work);
+       /* XXX: using scan_sdata is completely broken! */
        struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 
        if (local->hw.conf.flags & IEEE80211_CONF_PS)
                return;
 
-       if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)
+       if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK && sdata)
                ieee80211_send_nullfunc(local, sdata, 1);
 
        local->hw.conf.flags |= IEEE80211_CONF_PS;