Subject: Re: mac80211: holding sta_info for non associated stations
From: Johannes Berg <johannes@sipsolutions.net>
To: Ron Rindjunsky <ron.rindjunsky@intel.com>
Cc: "John W. Linville" <linville@tuxdriver.com>,
	"Winkler, Tomas" <tomas.winkler@intel.com>,
	linux-wireless <linux-wireless@vger.kernel.org>
In-Reply-To: <c85cb4470803310746h36b20d0egce98f8cea3becb0b@mail.gmail.com> (sfid-20080331_154705_823745_A1E01497)
References: <c85cb4470803310746h36b20d0egce98f8cea3becb0b@mail.gmail.com>
	 (sfid-20080331_154705_823745_A1E01497)
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Date: Tue, 01 Apr 2008 14:28:16 +0200
Message-Id: <1207052896.5143.76.camel@johannes.berg> (sfid-20080401_132827_754827_34641ADE)
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Hi,

> If i associate to a random AP "x" (what happened automatically as i
> was configured by ifup scripts to do that), and then scan and
> associate to my desired AP "y", i notice that AP "x" was not removed
> from the mac80211 station table. Then, what happened was that during
> ieee80211_stop, when we reach
>=20
> list_for_each_entry_rcu(sta, &local->sta_list, list) {
>     if (sta->sdata =3D=3D sdata)
>     ieee80211_sta_tear_down_BA_sessions(dev, sta->addr);
> }
>=20
> we try to tear down sessions to irrelevant stations (AP "x" in my
> example), which leads to bugs.

Why would that lead to bugs? That station was known, and there are no
sessions for that AP.

> did i miss something, or is there really a problem in the state
> machine in the described scenario?

There might be a problem in that we forget to remove that AP under some
circumstances but it shouldn't matter, we always can have multiple
stations in our table.

johannes

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