From 31f7a8c4fb08e18a1df3debc760be7a8280efada Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 12 Oct 2023 12:34:47 +0200 Subject: [PATCH] wifi: mac80211: fix change_address deadlock during unregister [ Upstream commit 74a7c93f45abba538914a65dd2ef2ea7cf7150e2 ] When using e.g. bonding, and doing a sequence such as # iw wlan0 set type __ap # ip link add name bond1 type bond # ip link set wlan0 master bond1 # iw wlan0 interface del we deadlock, since the wlan0 interface removal will cause bonding to reset the MAC address of wlan0. The locking would be somewhat difficult to fix, but since this only happens during removal, we can simply ignore the MAC address change at this time. Reported-by: syzbot+25b3a0b24216651bc2af@syzkaller.appspotmail.com Signed-off-by: Johannes Berg Link: https://lore.kernel.org/r/20231012123447.9f9d7fd1f237.Ic3a5ef4391b670941a69cec5592aefc79d9c2890@changeid Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/mac80211/iface.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 408ee5afc9ae..6a9d81e9069c 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -300,6 +300,14 @@ static int ieee80211_change_mac(struct net_device *dev, void *addr) struct ieee80211_local *local = sdata->local; int ret; + /* + * This happens during unregistration if there's a bond device + * active (maybe other cases?) and we must get removed from it. + * But we really don't care anymore if it's not registered now. + */ + if (!dev->ieee80211_ptr->registered) + return 0; + wiphy_lock(local->hw.wiphy); ret = _ieee80211_change_mac(sdata, addr); wiphy_unlock(local->hw.wiphy);