From 40c575d1ec71f7a61c73ba1603a69650c130559c Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 1 Feb 2021 19:20:50 +0100 Subject: cfg80211: fix netdev registration deadlock If register_netdevice() fails after having called cfg80211's netdev notifier (cfg80211_netdev_notifier_call) it will call the notifier again with UNREGISTER. This would then lock the wiphy mutex because we're marked as registered, which causes a deadlock. Fix this by separately keeping track of whether or not we're in the middle of registering to also skip the notifier call on this unregister. Reported-by: syzbot+2ae0ca9d7737ad1a62b7@syzkaller.appspotmail.com Fixes: a05829a7222e ("cfg80211: avoid holding the RTNL when calling the driver") Link: https://lore.kernel.org/r/20210201192048.ed8bad436737.I7cae042c44b15f80919a285799a15df467e9d42d@changeid Signed-off-by: Johannes Berg --- include/net/cfg80211.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include/net') diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index 4741d71ead21..4cdd75449d73 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -5299,6 +5299,8 @@ static inline void wiphy_unlock(struct wiphy *wiphy) * @wiphy: pointer to hardware description * @iftype: interface type * @registered: is this wdev already registered with cfg80211 + * @registering: indicates we're doing registration under wiphy lock + * for the notifier * @list: (private) Used to collect the interfaces * @netdev: (private) Used to reference back to the netdev, may be %NULL * @identifier: (private) Identifier used in nl80211 to identify this @@ -5382,7 +5384,7 @@ struct wireless_dev { struct mutex mtx; - bool use_4addr, is_running, registered; + bool use_4addr, is_running, registered, registering; u8 address[ETH_ALEN] __aligned(sizeof(u16)); -- cgit v1.2.3