When netdev registration fails or an interface cannot be moved out of a dying network namespace, the netdev core calls ->ndo_uninit() (ieee80211_uninit) with RTNL held. However, ieee80211_uninit() calls ieee80211_teardown_sdata() without holding wiphy_lock. During teardown, ieee80211_free_keys() invokes wiphy_delayed_work_cancel(), which triggers a lockdep warning: WARNING: CPU: 0 PID: 6112 at net/wireless/core.c:1839 wiphy_delayed_work_cancel+0x85/0xb0 ... Call Trace: ieee80211_free_keys+0x31a/0x3c0 net/mac80211/key.c:380 ieee80211_teardown_sdata+0x2b8/0x10f0 net/mac80211/iface.c:928 ieee80211_uninit+0x3f/0x50 net/mac80211/iface.c:954 rollback_registered_many+0xa5c/0xef0 net/core/dev.c:10065 In the normal deletion path (ieee80211_del_virtual_intf), both RTNL and wiphy_lock are held when ieee80211_teardown_sdata() runs, and the sdata is removed from local->interfaces. Change ieee80211_unlist_sdata() to return a boolean indicating whether the sdata was present in the list, and acquire wiphy_lock in ieee80211_uninit() only if the interface is actually being unlisted here. Reported-by: syzbot+e9cbd080a7801f06cf08@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=e9cbd080a7801f06cf08 Tested-by: syzbot+e9cbd080a7801f06cf08@syzkaller.appspotmail.com Signed-off-by: Raj Ojha --- net/mac80211/iface.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 5f0c482..175965f 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -931,7 +931,7 @@ static void ieee80211_teardown_sdata(struct ieee80211_sub_if_data *sdata) * core when cfg80211 couldn't move it out of a network namespace that's being * destroyed. Drop it from the interface list either way. */ -static void ieee80211_unlist_sdata(struct ieee80211_sub_if_data *sdata) +static bool ieee80211_unlist_sdata(struct ieee80211_sub_if_data *sdata) { struct ieee80211_local *local = sdata->local; struct ieee80211_sub_if_data *iter; @@ -943,16 +943,25 @@ static void ieee80211_unlist_sdata(struct ieee80211_sub_if_data *sdata) continue; guard(mutex)(&local->iflist_mtx); list_del_rcu(&sdata->list); - return; + return true; } + + return false; } static void ieee80211_uninit(struct net_device *dev) { struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev); + struct wiphy *wiphy = sdata->local->hw.wiphy; + bool unlisted = ieee80211_unlist_sdata(sdata); + + if (unlisted) + wiphy_lock(wiphy); - ieee80211_unlist_sdata(sdata); ieee80211_teardown_sdata(sdata); + + if (unlisted) + wiphy_unlock(wiphy); } static int ieee80211_netdev_setup_tc(struct net_device *dev, -- 2.47.0.windows.1