On 2019-03-01 16:29, Ben Greear wrote: > On 3/1/19 5:48 AM, Felix Fietkau wrote: >> There are several scenarios in which mac80211 can call drv_wake_tx_queue >> after ieee80211_restart_hw has been called and has not yet completed. >> Driver private structs are considered uninitialized until mac80211 has >> uploaded the vifs, stations and keys again, so using private tx queue >> data during that time is not safe. >> >> The driver can also not rely on drv_reconfig_complete to figure out when >> it is safe to accept drv_wake_tx_queue calls again, because it is only >> called after all tx queues are woken again. >> >> To fix this, bail out early in drv_wake_tx_queue if local->in_reconfig >> is set. > > This reminded me of a patch I posted back in 2016. The discussion just sort of > ended on it, but curious if you have a new opinion on it after debugging the > issue in this patch: > > https://patchwork.kernel.org/patch/9457709/ > > For what its worth, I've been using the patch above since I posted it, and > it seems to work well for ath9k and ath10k. I agree with what Johannes wrote about that patch. Fixing this could likely be as simple as clearing IEEE80211_SDATA_IN_DRIVER on all interfaces before bringing any of them back up. That way the normal interface add logic applies without nasty special cases. The reconfig code checks for ieee80211_sdata_running (which is unaffected), so I don't think we need to save the previous value of that flag. - Felix
