On 12.06.19 16:47, Sebastian Andrzej Siewior wrote: > 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. I just sent a patch for the underlying problem in the rt2x00 driver, see [1]. So we can drop this patch here and keep RT folks happy. I really hope that no other usb drivers are affected by similar problems. Zyxel support just sent me (some?) source code for the firmware of my internet router (my real problem I mentioned before). Need to look into this... Thanks for your help, Soeren [1] https://lkml.org/lkml/2019/6/17/238 >> Alan Stern > Sebastian
