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mac80211: sync acccess to tx_filtered/ps_tx_buf queues

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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>
This commit is contained in:
Arik Nemtsov 2012-11-05 10:27:52 +02:00 committed by Johannes Berg
parent bca1e29fb5
commit 987c285c2a
1 changed files with 5 additions and 0 deletions
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5
net/mac80211/sta_info.c
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@ -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;
}