Messages in this thread | | | Date | Wed, 21 Sep 2022 08:03:04 -0700 | Subject | Re: [PATCH 1/2] cfg80211: fix dead lock for nl80211_new_interface() | From | Jeff Johnson <> |
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On 9/21/2022 2:19 AM, Aran Dalton wrote: > Both nl80211_new_interface and cfg80211_netdev_notifier_call hold the > same wiphy_lock, then cause deadlock. > > The main call stack as bellow: > > nl80211_new_interface() takes wiphy_lock > -> _nl80211_new_interface: > -> rdev_add_virtual_intf > -> rdev->ops->add_virtual_intf > -> register_netdevice > -> call_netdevice_notifiers(NETDEV_REGISTER, dev); > -> call_netdevice_notifiers_extack > -> call_netdevice_notifiers_info > -> raw_notifier_call_chain > -> cfg80211_netdev_notifier_call > -> wiphy_lock(&rdev->wiphy), cfg80211_register_wdev
In both of your patches please describe what you are doing in the patch to fix the problem, and in particular describe why your fix is safe.
> > Fixes: ea6b2098dd02 ("cfg80211: fix locking in netlink owner interface destruction") > Signed-off-by: Aran Dalton <arda@allwinnertech.com> > --- > net/wireless/nl80211.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c > index 2705e3ee8fc4..bdacddc3ffa3 100644 > --- a/net/wireless/nl80211.c > +++ b/net/wireless/nl80211.c > @@ -4260,9 +4260,7 @@ static int nl80211_new_interface(struct sk_buff *skb, struct genl_info *info) > /* to avoid failing a new interface creation due to pending removal */ > cfg80211_destroy_ifaces(rdev); > > - wiphy_lock(&rdev->wiphy); > ret = _nl80211_new_interface(skb, info); > - wiphy_unlock(&rdev->wiphy); > > return ret; > }
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