[ 3.5.y.z extended stable ] Patch "mac80211: sync acccess to tx_filtered/ps_tx_buf queues" has been added to staging queue

Herton Ronaldo Krzesinski herton.krzesinski at canonical.com
Fri Dec 7 16:04:35 UTC 2012

This is a note to let you know that I have just added a patch titled

    mac80211: sync acccess to tx_filtered/ps_tx_buf queues

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:


If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see



>From 831921bd7b34f5fea8be2e49e77890f12c74c944 Mon Sep 17 00:00:00 2001
From: Arik Nemtsov <arik at wizery.com>
Date: Mon, 5 Nov 2012 10:27:52 +0200
Subject: [PATCH] mac80211: sync acccess to tx_filtered/ps_tx_buf queues

commit 987c285c2ae2e4e32aca3a9b3252d28171c75711 upstream.

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

Signed-off-by: Arik Nemtsov <arik at wizery.com>
Signed-off-by: Ido Yariv <ido at wizery.com>
Signed-off-by: Johannes Berg <johannes.berg at intel.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
 net/mac80211/sta_info.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 277bd96..343484c 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -959,6 +959,7 @@ 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);

@@ -974,12 +975,16 @@ 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;

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