From 33ddd81e2bd5d9970b9f01ab383ba45035fa41ee Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Mon, 13 Nov 2017 11:33:55 +0100
Subject: [PATCH] mac80211: properly free requested-but-not-started TX agg sessions
Git-commit: 33ddd81e2bd5d9970b9f01ab383ba45035fa41ee
Patch-mainline: v4.15-rc1
References: FATE#326294
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 <fengguang.wu@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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);
--
2.19.2