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>

1 files changed, 5 insertions, 0 deletions

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 797dd36a220d..89ccd3ec7eb8 100644
--- 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;
         }