[4.2.y-ckt stable] Patch "mac80211: properly deal with station hashtable insert errors" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    mac80211: properly deal with station hashtable insert errors

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt8.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 1acb0f77df396963190e9fae0b498885d4b0190e Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg at intel.com>
Date: Thu, 31 Mar 2016 17:22:45 +0200
Subject: mac80211: properly deal with station hashtable insert errors

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 at candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg at intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/mac80211/sta_info.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 3389959..b2a9445 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -253,11 +253,11 @@ void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
 }

 /* 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)
@@ -499,7 +499,9 @@ static int sta_info_insert_finish(struct sta_info *sta) __acquires(RCU)
 	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);

@@ -533,6 +535,7 @@ static int sta_info_insert_finish(struct sta_info *sta) __acquires(RCU)
  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);
--
2.7.4