Re: mac80211: holding sta_info for non associated stations

[Johannes Berg <johannes@sipsolutions.net>]

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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
> 
> list_for_each_entry_rcu(sta, &local->sta_list, list) {
>     if (sta->sdata == sdata)
>     ieee80211_sta_tear_down_BA_sessions(dev, sta->addr);
> }
> 
> 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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