[PATCH v2] wifi: cfg80211: use wiphy work for socket owner autodisconnect

[PATCH v2] wifi: cfg80211: use wiphy work for socket owner autodisconnect

[Cen Zhang]

nl80211_netlink_notify() walks the cfg80211 wireless device list when a
NETLINK_GENERIC socket is released. If the socket owns a connection, the
notifier queues the embedded wdev->disconnect_wk work item.

That work is a plain work_struct today. NETDEV_GOING_DOWN cancels it, but a
NETLINK_URELEASE notifier that already observed conn_owner_nlportid can
queue it after that cancel returns. _cfg80211_unregister_wdev() then
removes the wdev from the list and waits for RCU readers, but
synchronize_net() does not drain work queued by such a reader.

Make the autodisconnect work a wiphy_work instead. The callback already
needs the wiphy mutex, and wiphy_work runs under that mutex. This lets
teardown cancel pending autodisconnect work while holding the mutex,
without a cancel_work_sync() vs. worker locking concern.

Also cancel the wiphy work after list_del_rcu() and synchronize_net(). Any
NETLINK_URELEASE notifier that had already reached the wdev list has then
either queued the work and it is removed, or can no longer find the wdev.

Fixes: bd2522b16884 ("cfg80211: NL80211_ATTR_SOCKET_OWNER support for CMD_CONNECT")
Suggested-by: Johannes Berg <johannes@sipsolutions.net>
Assisted-by: Codex:gpt-5.5
Signed-off-by: Cen Zhang <zzzccc427@gmail.com>
---
v2:
- Convert the autodisconnect work to wiphy_work instead of taking RTNL in
  nl80211_netlink_notify().
- Add a final wiphy_work_cancel() after list_del_rcu()/synchronize_net().

 include/net/cfg80211.h |  2 +-
 net/wireless/core.c    | 10 ++++++----
 net/wireless/core.h    |  2 +-
 net/wireless/nl80211.c |  3 ++-
 net/wireless/sme.c     |  6 ++----
 5 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 8188ad200de5..76827c965f41 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -7228,7 +7228,7 @@ struct wireless_dev {
 	enum ieee80211_bss_type conn_bss_type;
 	u32 conn_owner_nlportid;
 
-	struct work_struct disconnect_wk;
+	struct wiphy_work disconnect_wk;
 	u8 disconnect_bssid[ETH_ALEN];
 
 	struct list_head event_list;
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 3dcf63b04c41..de86464695ba 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -1424,6 +1424,7 @@ static void _cfg80211_unregister_wdev(struct wireless_dev *wdev,
 	list_del_rcu(&wdev->list);
 	synchronize_net();
 	rdev->devlist_generation++;
+	wiphy_work_cancel(wdev->wiphy, &wdev->disconnect_wk);
 
 	cfg80211_mlme_purge_registrations(wdev);
 
@@ -1637,7 +1638,7 @@ void cfg80211_init_wdev(struct wireless_dev *wdev)
 	     wdev->iftype == NL80211_IFTYPE_ADHOC) && !wdev->use_4addr)
 		wdev->netdev->priv_flags |= IFF_DONT_BRIDGE;
 
-	INIT_WORK(&wdev->disconnect_wk, cfg80211_autodisconnect_wk);
+	wiphy_work_init(&wdev->disconnect_wk, cfg80211_autodisconnect_wk);
 }
 
 void cfg80211_register_wdev(struct cfg80211_registered_device *rdev,
@@ -1743,10 +1744,11 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
 		break;
 	case NETDEV_GOING_DOWN:
 		cfg80211_leave(rdev, wdev, -1);
-		scoped_guard(wiphy, &rdev->wiphy)
+		scoped_guard(wiphy, &rdev->wiphy) {
 			cfg80211_remove_links(wdev);
-		/* since we just did cfg80211_leave() nothing to do there */
-		cancel_work_sync(&wdev->disconnect_wk);
+			/* since we just did cfg80211_leave() nothing to do there */
+			wiphy_work_cancel(wdev->wiphy, &wdev->disconnect_wk);
+		}
 		cancel_work_sync(&wdev->pmsr_free_wk);
 		break;
 	case NETDEV_DOWN:
diff --git a/net/wireless/core.h b/net/wireless/core.h
index df47ed6208a5..f343d1074ace 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -428,7 +428,7 @@ void __cfg80211_port_authorized(struct wireless_dev *wdev, const u8 *peer_addr,
 				const u8 *td_bitmap, u8 td_bitmap_len);
 int cfg80211_mgd_wext_connect(struct cfg80211_registered_device *rdev,
 			      struct wireless_dev *wdev);
-void cfg80211_autodisconnect_wk(struct work_struct *work);
+void cfg80211_autodisconnect_wk(struct wiphy *wiphy, struct wiphy_work *work);
 
 /* SME implementation */
 void cfg80211_conn_work(struct work_struct *work);
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 53b4b3f76697..153a9e8f35eb 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -22942,7 +22942,8 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
 				wdev->nl_owner_dead = true;
 				schedule_work(&rdev->destroy_work);
 			} else if (wdev->conn_owner_nlportid == notify->portid) {
-				schedule_work(&wdev->disconnect_wk);
+				wiphy_work_queue(wdev->wiphy,
+						 &wdev->disconnect_wk);
 			}
 
 			cfg80211_release_pmsr(wdev, notify->portid);
diff --git a/net/wireless/sme.c b/net/wireless/sme.c
index b451df3096dd..2a719b5c487e 100644
--- a/net/wireless/sme.c
+++ b/net/wireless/sme.c
@@ -1578,13 +1578,11 @@ int cfg80211_disconnect(struct cfg80211_registered_device *rdev,
  * Used to clean up after the connection / connection attempt owner socket
  * disconnects
  */
-void cfg80211_autodisconnect_wk(struct work_struct *work)
+void cfg80211_autodisconnect_wk(struct wiphy *wiphy, struct wiphy_work *work)
 {
 	struct wireless_dev *wdev =
 		container_of(work, struct wireless_dev, disconnect_wk);
-	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wdev->wiphy);
-
-	guard(wiphy)(wdev->wiphy);
+	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 
 	if (wdev->conn_owner_nlportid) {
 		switch (wdev->iftype) {
-- 
2.43.0