From d305a6557b2c4dca0110f05ffe745b1ef94adb80 Mon Sep 17 00:00:00 2001 From: Nikolay Martynov Date: Mon, 28 Nov 2011 09:18:00 +0100 Subject: mac80211: fix race condition caused by late addBA response If addBA responses comes in just after addba_resp_timer has expired mac80211 will still accept it and try to open the aggregation session. This causes drivers to be confused and in some cases even crash. This patch fixes the race condition and makes sure that if addba_resp_timer has expired addBA response is not longer accepted and we do not try to open half-closed session. Cc: stable@vger.kernel.org Signed-off-by: Nikolay Martynov [some adjustments] Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/agg-tx.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c index 674b345ade8..eea6e5c8d16 100644 --- a/net/mac80211/agg-tx.c +++ b/net/mac80211/agg-tx.c @@ -762,11 +762,27 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local, goto out; } - del_timer(&tid_tx->addba_resp_timer); + del_timer_sync(&tid_tx->addba_resp_timer); #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid); #endif + + /* + * addba_resp_timer may have fired before we got here, and + * caused WANT_STOP to be set. If the stop then was already + * processed further, STOPPING might be set. + */ + if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) || + test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) { +#ifdef CONFIG_MAC80211_HT_DEBUG + printk(KERN_DEBUG + "got addBA resp for tid %d but we already gave up\n", + tid); +#endif + goto out; + } + /* * IEEE 802.11-2007 7.3.1.14: * In an ADDBA Response frame, when the Status Code field -- cgit v1.2.3