[PATCH net v2] mac802154: remove interfaces with RCU list deletion

[Yousef Alhouseen <alhouseenyousef@gmail.com>]

Queue wake, stop, and disable paths walk local->interfaces under RCU.
The bulk hardware teardown path removes entries with list_del(), so an
asynchronous transmit completion can follow a poisoned list node in
ieee802154_wake_queue().

Use list_del_rcu() as in the single-interface removal path. The following
unregister_netdevice() waits for in-flight RCU readers before freeing the
netdevice, so no separate grace-period wait is needed.

Fixes: 592dfbfc72f5 ("mac820154: move interface unregistration into iface")
Reported-by: syzbot+36256deb69a588e9290e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=36256deb69a588e9290e
Cc: stable@vger.kernel.org
Signed-off-by: Yousef Alhouseen <alhouseenyousef@gmail.com>
---
Changes in v2:
- Drop the redundant synchronize_rcu() noted by Kuniyuki Iwashima.
- Clarify that unregister_netdevice() supplies the required RCU wait.
- Narrow the subject and commit message to the list deletion bug.

 net/mac802154/iface.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac802154/iface.c b/net/mac802154/iface.c
index 000be60d9580..b823720630e7 100644
--- a/net/mac802154/iface.c
+++ b/net/mac802154/iface.c
@@ -703,7 +703,7 @@ void ieee802154_remove_interfaces(struct ieee802154_local *local)
 
 	mutex_lock(&local->iflist_mtx);
 	list_for_each_entry_safe(sdata, tmp, &local->interfaces, list) {
-		list_del(&sdata->list);
+		list_del_rcu(&sdata->list);
 
 		unregister_netdevice(sdata->dev);
 	}
-- 
2.55.0