mac80211: fix aggregation timer lockups

As far as I can tell, there are possible lockups because both the RX
session_timer and TX addba_resp_timer are del_timer_sync'ed under
the sta spinlock which both timer functions take. Additionally, the
TX agg code seems to leak memory when TX aggregation is not disabled
before the sta_info is freed.

Fix this by making the free code a little smarter in the RX agg case,
and actually make the sta_info_destroy code free the TX agg info in
the TX agg case. We won't notify the peer, but it'll notice something
is wrong anyway, and normally this only happens after we've told it
in some other way we will no longer talk to it.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index d7afd0956970..4b571b211625 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();
 }