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From:   gregory.greenman@intel.com
To:     johannes@sipsolutions.net
Cc:     linux-wireless@vger.kernel.org,
        Benjamin Berg <benjamin.berg@intel.com>,
        Gregory Greenman <gregory.greenman@intel.com>
Subject: [PATCH 06/15] wifi: mac80211: take lock before setting vif links
Date:   Thu,  8 Jun 2023 16:36:02 +0300
Message-Id: <20230608163202.fa0c6597fdad.I83dd70359f6cda30f86df8418d929c2064cf4995@changeid>
In-Reply-To: <20230608133611.1303724-1-gregory.greenman@intel.com>
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From: Benjamin Berg <benjamin.berg@intel.com>

ieee80211_vif_set_links requires the sdata->local->mtx lock to be held.
Add the appropriate locking around the calls in both the link add and
remove handlers.

This causes a warning when e.g. ieee80211_link_release_channel is called
via ieee80211_link_stop from ieee80211_vif_update_links.

Fixes: 0d8c4a3c8688 ("wifi: mac80211: implement add/del interface link callbacks")
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
---
 net/mac80211/cfg.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 1b78a2ae7a83..4aaead4895b7 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -4862,11 +4862,16 @@ static int ieee80211_add_intf_link(struct wiphy *wiphy,
 				   unsigned int link_id)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
+	int res;
 
 	if (wdev->use_4addr)
 		return -EOPNOTSUPP;
 
-	return ieee80211_vif_set_links(sdata, wdev->valid_links);
+	mutex_lock(&sdata->local->mtx);
+	res = ieee80211_vif_set_links(sdata, wdev->valid_links);
+	mutex_unlock(&sdata->local->mtx);
+
+	return res;
 }
 
 static void ieee80211_del_intf_link(struct wiphy *wiphy,
@@ -4875,7 +4880,9 @@ static void ieee80211_del_intf_link(struct wiphy *wiphy,
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
 
+	mutex_lock(&sdata->local->mtx);
 	ieee80211_vif_set_links(sdata, wdev->valid_links);
+	mutex_unlock(&sdata->local->mtx);
 }
 
 static int sta_add_link_station(struct ieee80211_local *local,
-- 
2.38.1