From: Johannes Berg <[email protected]> When deleting a station or otherwise tearing down all aggregation sessions, make sure to delete requested but not yet started ones, to avoid the following scenario:
* session is requested, added to tid_start_tx[] * ieee80211_ba_session_work() runs, gets past BLOCK_BA check * ieee80211_sta_tear_down_BA_sessions() runs, locks &sta->ampdu_mlme.mtx, e.g. while deleting the station - deleting all active sessions * ieee80211_ba_session_work() continues since tear down flushes it, and calls ieee80211_tx_ba_session_handle_start() for the new session, arms the timer for it * station deletion continues to __cleanup_single_sta() and frees the session struct, while the timer is armed Reported-by: Fengguang Wu <[email protected]> Signed-off-by: Johannes Berg <[email protected]> --- net/mac80211/agg-tx.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c index 3680b380e70c..5f8ab5be369f 100644 --- a/net/mac80211/agg-tx.c +++ b/net/mac80211/agg-tx.c @@ -330,6 +330,11 @@ int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid, spin_lock_bh(&sta->lock); + /* free struct pending for start, if present */ + tid_tx = sta->ampdu_mlme.tid_start_tx[tid]; + kfree(tid_tx); + sta->ampdu_mlme.tid_start_tx[tid] = NULL; + tid_tx = rcu_dereference_protected_tid_tx(sta, tid); if (!tid_tx) { spin_unlock_bh(&sta->lock); -- 2.14.2
