[PATCH 4.18 002/168] mac80211: Run TXQ teardown code before de-registering interfaces

[Greg Kroah-Hartman]

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

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

From: "Toke Hød-Jøsen" <toke@xxxxxxx>

[ Upstream commit 77cfaf52eca5cac30ed029507e0cab065f888995 ]

The TXQ teardown code can reference the vif data structures that are
stored in the netdev private memory area if there are still packets on
the queue when it is being freed. Since the TXQ teardown code is run
after the netdevs are freed, this can lead to a use-after-free. Fix this
by moving the TXQ teardown code to earlier in ieee80211_unregister_hw().

Reported-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Tested-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Signed-off-by: Toke HÃiland-JÃrgensen <toke@xxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/mac80211/main.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -1182,6 +1182,7 @@ void ieee80211_unregister_hw(struct ieee
 #if IS_ENABLED(CONFIG_IPV6)
 	unregister_inet6addr_notifier(&local->ifa6_notifier);
 #endif
+	ieee80211_txq_teardown_flows(local);
 
 	rtnl_lock();
 
@@ -1210,7 +1211,6 @@ void ieee80211_unregister_hw(struct ieee
 	skb_queue_purge(&local->skb_queue);
 	skb_queue_purge(&local->skb_queue_unreliable);
 	skb_queue_purge(&local->skb_queue_tdls_chsw);
-	ieee80211_txq_teardown_flows(local);
 
 	destroy_workqueue(local->workqueue);
 	wiphy_unregister(local->hw.wiphy);