On 2019-06-12 10:38:11 [-0400], Alan Stern wrote: > > > > When stopping hostapd after it hangs: > > [ 903.504475] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue > > 14 failed to flush > > Instead of reverting the original commit, can you prevent the problem > by adding local_irq_save() and local_irq_restore() to the URB > completion routines in that wireless driver? > > Probably people who aren't already pretty familiar with the driver code > won't easily be able to locate the race. Still, a little overkill may > be an acceptable solution. Not from RT point of view because you do local_irq_save() -> spin_lock() but it might be worth checking if the local_irq_save() within that wireless driver avoids the race or not. > Alan Stern Sebastian