On 2019-03-01 17:06, Felix Fietkau wrote: > 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. How about this? (untested) --- --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -1956,7 +1956,6 @@ static void ieee80211_flush_completed_scan(struct ieee80211_local *local, static void ieee80211_handle_reconfig_failure(struct ieee80211_local *local) { - struct ieee80211_sub_if_data *sdata; struct ieee80211_chanctx *ctx; /* @@ -1980,9 +1979,6 @@ static void ieee80211_handle_reconfig_failure(struct ieee80211_local *local) */ ieee80211_sched_scan_end(local); - list_for_each_entry(sdata, &local->interfaces, list) - sdata->flags &= ~IEEE80211_SDATA_IN_DRIVER; - /* Mark channel contexts as not being in the driver any more to avoid * removing them from the driver during the shutdown process... */ @@ -2135,6 +2131,9 @@ int ieee80211_reconfig(struct ieee80211_local *local) local->started = false; + list_for_each_entry(sdata, &local->interfaces, list) + sdata->flags &= ~IEEE80211_SDATA_IN_DRIVER; + /* * Upon resume hardware can sometimes be goofy due to * various platform / driver / bus issues, so restarting
