3 files changed, 43 insertions, 6 deletions

diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index d7afd09..4b571b2 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -78,11 +78,18 @@ void ieee80211_sta_stop_rx_ba_session(struct ieee80211_sub_if_data *sdata, u8 *r
 			sta->ampdu_mlme.tid_rx[tid]->reorder_buf[i] = NULL;
 		}
 	}
+
+	spin_lock_bh(&sta->lock);
 	/* free resources */
 	kfree(sta->ampdu_mlme.tid_rx[tid]->reorder_buf);
-	kfree(sta->ampdu_mlme.tid_rx[tid]);
-	sta->ampdu_mlme.tid_rx[tid] = NULL;
+
+	if (!sta->ampdu_mlme.tid_rx[tid]->shutdown) {
+		kfree(sta->ampdu_mlme.tid_rx[tid]);
+		sta->ampdu_mlme.tid_rx[tid] = NULL;
+	}
+
 	sta->ampdu_mlme.tid_state_rx[tid] = HT_AGG_STATE_IDLE;
+	spin_unlock_bh(&sta->lock);
 
 	rcu_read_unlock();
 }
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 10c5539..634f65c 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -194,12 +194,41 @@ void sta_info_destroy(struct sta_info *sta)
 		dev_kfree_skb_any(skb);
 
 	for (i = 0; i <  STA_TID_NUM; i++) {
+		struct tid_ampdu_rx *tid_rx;
+		struct tid_ampdu_tx *tid_tx;
+
 		spin_lock_bh(&sta->lock);
-		if (sta->ampdu_mlme.tid_rx[i])
-		  del_timer_sync(&sta->ampdu_mlme.tid_rx[i]->session_timer);
-		if (sta->ampdu_mlme.tid_tx[i])
-		  del_timer_sync(&sta->ampdu_mlme.tid_tx[i]->addba_resp_timer);
+		tid_rx = sta->ampdu_mlme.tid_rx[i];
+		/* Make sure timer won't free the tid_rx struct, see below */
+		if (tid_rx)
+			tid_rx->shutdown = true;
 		spin_unlock_bh(&sta->lock);
+
+		/*
+		 * Outside spinlock - shutdown is true now so that the timer
+		 * won't free tid_rx, we have to do that now. Can't let the
+		 * timer do it because we have to sync the timer outside the
+		 * lock that it takes itself.
+		 */
+		if (tid_rx) {
+			del_timer_sync(&tid_rx->session_timer);
+			kfree(tid_rx);
+		}
+
+		/*
+		 * No need to do such complications for TX agg sessions, the
+		 * path leading to freeing the tid_tx struct goes via a call
+		 * from the driver, and thus needs to look up the sta struct
+		 * again, which cannot be found when we get here. Hence, we
+		 * just need to delete the timer and free the aggregation
+		 * info; we won't be telling the peer about it then but that
+		 * doesn't matter if we're not talking to it again anyway.
+		 */
+		tid_tx = sta->ampdu_mlme.tid_tx[i];
+		if (tid_tx) {
+			del_timer_sync(&tid_tx->addba_resp_timer);
+			kfree(tid_tx);
+		}
 	}
 
 	__sta_info_free(local, sta);
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index a070bd9..d965323 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -100,6 +100,7 @@ struct tid_ampdu_rx {
 	u16 buf_size;
 	u16 timeout;
 	u8 dialog_token;
+	bool shutdown;
 };
 
 /**