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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 6/9] wifi: mac80211: avoid lockdep checking when removing deflink
Date:   Mon, 19 Jun 2023 16:26:50 +0300
Message-Id: <20230619161906.cdd81377dea0.If5a6734b4b85608a2275a09b4f99b5564d82997f@changeid>
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From: Benjamin Berg <benjamin.berg@intel.com>

struct sta_info may be removed without holding sta_mtx if it has not
yet been inserted. To support this, only assert that the lock is held
for links other than the deflink.

This fixes lockdep issues that may be triggered in error cases.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
---
 net/mac80211/sta_info.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 731b832b257c..7751f8ba960e 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -355,8 +355,9 @@ static void sta_remove_link(struct sta_info *sta, unsigned int link_id,
 	struct sta_link_alloc *alloc = NULL;
 	struct link_sta_info *link_sta;
 
-	link_sta = rcu_dereference_protected(sta->link[link_id],
-					     lockdep_is_held(&sta->local->sta_mtx));
+	link_sta = rcu_access_pointer(sta->link[link_id]);
+	if (link_sta != &sta->deflink)
+		lockdep_assert_held(&sta->local->sta_mtx);
 
 	if (WARN_ON(!link_sta))
 		return;
-- 
2.38.1