Re: [PATCH v2] mac80211: reject station addition if AP or MLO link is inactive

[Slawomir Stepien <sst@poczta.fm>]

On lip 27, 2026 10:19, Johannes Berg wrote:
> Hi,
> 
> On Mon, 2026-07-27 at 09:45 +0200, Slawomir Stepien wrote:
> > Currently, userspace can issue a netlink command to add a station to
> > an AP or P2P GO interface before the AP has fully started, or before
> > a specific MLO link has begun beaconing. This will e.g. lead to a
> > WARN_ON trigger:
> > 
> > WARNING: net/mac80211/rate.c:51 at rate_control_rate_init+0x5a6/0x630
> > ...
> > Call Trace:
> >  <TASK>
> >  rate_control_rate_init_all_links+0xf4/0x190 net/mac80211/rate.c:84
> >  sta_apply_auth_flags+0x1bc/0x430 net/mac80211/cfg.c:2152
> >  sta_apply_parameters+0x126d/0x1b10 net/mac80211/cfg.c:2618
> >  ieee80211_add_station+0x3de/0x700 net/mac80211/cfg.c:2684
> >  rdev_add_station+0xfc/0x290 net/wireless/rdev-ops.h:201
> >  nl80211_new_station+0x1b4e/0x1fd0 net/wireless/nl80211.c:9505
> > 
> > Fix this by introducing a two-tiered active state check in
> > ieee80211_add_station():
> 
> Shouldn't we have enough information in cfg80211 to validate it there,
> benefiting other drivers?

I think we do not have. I'm looking at the struct wireless_dev fields and I see that there is just
info about what the configuration should be, not info about what is the current state of the device.
I also do not see any callback in struct cfg80211_ops that might help to get such info. If I'm wrong
then please correct my observation!

Beside this, do we think that all devices would always need this rejection? What if firmware of
these devices would benefit from *lack* of such rejection? Just thinking aloud, not that I know such
devices.

-- 
Slawomir Stepien