From aa4545806025c63ec12cfe17528de16dca36b785 Mon Sep 17 00:00:00 2001 From: Helmut Schaa Date: Wed, 7 Mar 2012 17:20:30 +0100 Subject: [PATCH] mac80211: Limit TID buffering during BA session setup/teardown While setting up or tearing down a BA session mac80211 is buffering pending frames for the according TID. However, there's currently no limit on how many frames are buffered possibly leading to an out-of- memory situation. This can happen on systems with little memory when the CPU is fully loaded since the BA session work is executed in process context while frames can still come via softirq. Apply a limitation to the TIDs pending queue to avoid consuming too much memory in this situation. Signed-off-by: Helmut Schaa Signed-off-by: John W. Linville --- net/mac80211/tx.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 570737d..d9e791d 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1065,6 +1065,7 @@ static bool ieee80211_tx_prep_agg(struct ieee80211_tx_data *tx, { bool queued = false; bool reset_agg_timer = false; + struct sk_buff *purge_skb = NULL; if (test_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state)) { info->flags |= IEEE80211_TX_CTL_AMPDU; @@ -1106,8 +1107,13 @@ static bool ieee80211_tx_prep_agg(struct ieee80211_tx_data *tx, info->control.vif = &tx->sdata->vif; info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING; __skb_queue_tail(&tid_tx->pending, skb); + if (skb_queue_len(&tid_tx->pending) > STA_MAX_TX_BUFFER) + purge_skb = __skb_dequeue(&tid_tx->pending); } spin_unlock(&tx->sta->lock); + + if (purge_skb) + dev_kfree_skb(purge_skb); } /* reset session timer */ -- 2.7.4