[PATCH 4.4 098/137] mac80211: properly deal with station hashtable insert errors

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johannes Berg <johannes.berg@xxxxxxxxx>

commit 62b14b241ca6f790a17ccd9dd9f62ce1b006d406 upstream.

The original hand-implemented hash-table in mac80211 couldn't result
in insertion errors, and while converting to rhashtable I evidently
forgot to check the errors.

This surfaced now only because Ben is adding many identical keys and
that resulted in hidden insertion errors.

Fixes: 7bedd0cfad4e1 ("mac80211: use rhashtable for station table")
Reported-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/mac80211/sta_info.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -256,11 +256,11 @@ void sta_info_free(struct ieee80211_loca
 }
 
 /* Caller must hold local->sta_mtx */
-static void sta_info_hash_add(struct ieee80211_local *local,
-			      struct sta_info *sta)
+static int sta_info_hash_add(struct ieee80211_local *local,
+			     struct sta_info *sta)
 {
-	rhashtable_insert_fast(&local->sta_hash, &sta->hash_node,
-			       sta_rht_params);
+	return rhashtable_insert_fast(&local->sta_hash, &sta->hash_node,
+				      sta_rht_params);
 }
 
 static void sta_deliver_ps_frames(struct work_struct *wk)
@@ -503,7 +503,9 @@ static int sta_info_insert_finish(struct
 	set_sta_flag(sta, WLAN_STA_BLOCK_BA);
 
 	/* make the station visible */
-	sta_info_hash_add(local, sta);
+	err = sta_info_hash_add(local, sta);
+	if (err)
+		goto out_drop_sta;
 
 	list_add_tail_rcu(&sta->list, &local->sta_list);
 
@@ -538,6 +540,7 @@ static int sta_info_insert_finish(struct
  out_remove:
 	sta_info_hash_del(local, sta);
 	list_del_rcu(&sta->list);
+ out_drop_sta:
 	local->num_sta--;
 	synchronize_net();
 	__cleanup_single_sta(sta);