In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211_hwsim: don't hand frames to mac80211 while stopping

The code checks ->started for frames coming from wmediumd, but the
radio can be stopped after the check and before frame delivery,
causing mac80211 to hit the WARN_ON(!local->started).

Expand the mutex for this case and synchronise against it when the
radio is stopped to avoid being able to hit the warning with hwsim.

Drop the error print that would've complicated the error path, it
only triggers for allocation failures (already noisy) and malformed
frames anyway.