2012-11-05 08:27:57

by Arik Nemtsov

Subject: [PATCH] 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: [email protected]
Signed-off-by: Arik Nemtsov <[email protected]>
Signed-off-by: Ido Yariv <[email protected]>
---
And now with the correct address of stable :)

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 f7bb54f..f14655f 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -982,6 +982,7 @@ 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);

@@ -997,12 +998,16 @@ 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;
}
--
1.7.9.5

2012-11-05 13:20:49

by Johannes Berg

Subject: Re: [PATCH] mac80211: sync acccess to tx_filtered/ps_tx_buf queues

On Mon, 2012-11-05 at 10:27 +0200, Arik Nemtsov wrote:
> 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: [email protected]
> Signed-off-by: Arik Nemtsov <[email protected]>
> Signed-off-by: Ido Yariv <[email protected]>

Applied, thanks!

johannes