mac80211: sync acccess to tx_filtered/ps_tx_buf queues

These are accessed without a lock when ending STA PSM. If the
sta_cleanup timer accesses these lists at the same time, we might crash.

This may fix some mysterious crashes we had during
ieee80211_sta_ps_deliver_wakeup.

Cc: stable@vger.kernel.org
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Ido Yariv <ido@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 797dd36a220d92ac549067a9cd4d59a7ebfc09a3..89ccd3ec7eb87dac396fe5e257d5d792aa95f023 100644 (file)
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -961,6 +961,7 @@ void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta)
        struct ieee80211_local *local = sdata->local;
        struct sk_buff_head pending;
        int filtered = 0, buffered = 0, ac;
+       unsigned long flags;
 
        clear_sta_flag(sta, WLAN_STA_SP);
 
@@ -976,12 +977,16 @@ void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta)
        for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
                int count = skb_queue_len(&pending), tmp;
 
+               spin_lock_irqsave(&sta->tx_filtered[ac].lock, flags);
                skb_queue_splice_tail_init(&sta->tx_filtered[ac], &pending);
+               spin_unlock_irqrestore(&sta->tx_filtered[ac].lock, flags);
                tmp = skb_queue_len(&pending);
                filtered += tmp - count;
                count = tmp;
 
+               spin_lock_irqsave(&sta->ps_tx_buf[ac].lock, flags);
                skb_queue_splice_tail_init(&sta->ps_tx_buf[ac], &pending);
+               spin_unlock_irqrestore(&sta->ps_tx_buf[ac].lock, flags);
                tmp = skb_queue_len(&pending);
                buffered += tmp - count;
        }