Re: [PATCH 06/13] cfg80211: track monitor interfaces count

[Johannes Berg <johannes@xxxxxxxxxxxxxxxx>]

On Wed, 2012-07-04 at 13:26 +0200, Johannes Berg wrote:
> On Wed, 2012-07-04 at 13:17 +0200, Johannes Berg wrote:
> > On Wed, 2012-07-04 at 13:12 +0200, Johannes Berg wrote:
> > > Hi Michal,
> > > 
> > > A few people noticed that these patches cause deadlocks. I think the
> > > reason is that it's not allowed to lock the device here:
> > > 
> > > >  	case NETDEV_DOWN:
> > > >  		dev_hold(dev);
> > > > +		cfg80211_lock_rdev(rdev);
> > > 
> > > This causes a deadlock since the interface is set down inside mac80211
> > > when inside a handler from cfg80211 already, or so.
> > 
> > I just reproduce it -- it's because we come from nl80211_del_interface()
> 
> Ok ... we don't really need to hold the rdev lock since it's all under
> rtnl. Can you please confirm this is safe?
> 
> http://p.sipsolutions.net/bde4760671f3e250.txt

I guess we can remove more locking:
http://p.sipsolutions.net/8a1b875a431e72a0.txt

johannes

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