Commit b33fb28c authored by Loic Poulain's avatar Loic Poulain Committed by Johannes Berg
Browse files

mac80211: Prevent AP probing during suspend 



Submitting AP probe/null during suspend can cause unexpected
disconnect on resume because of timeout waiting for ack status:

wlan0: Failed to send nullfunc to AP 11:22:33:44:55:66 after 500ms, disconnecting

This is especially the case when we enter suspend when a scan is
ongoing, indeed, scan is cancelled from __ieee80211_suspend, leading
to a corresponding (aborted) scan complete event, which in turn causes
the submission of an immediate monitor null frame (restart_sta_timer).
The corresponding packet or ack will not be processed before resuming,
causing a timeout & disconnect on resume.

Delay the AP probing when suspending/suspended.

Signed-off-by: default avatarLoic Poulain <loic.poulain@linaro.org>
Link: https://lore.kernel.org/r/1634805927-1113-1-git-send-email-loic.poulain@linaro.org


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 63fa0426

net/mac80211/ieee80211_i.h

+3 −0
Original line number Diff line number Diff line
@@ -1241,6 +1241,9 @@ struct ieee80211_local { 
	 */

	bool suspended;



	/* suspending is true during the whole suspend process */

	bool suspending;



	/*

	 * Resuming is true while suspended, but when we're reprogramming the

	 * hardware -- at that time it's allowed to use ieee80211_queue_work()

net/mac80211/mlme.c

+7 −0
Original line number Diff line number Diff line
@@ -2589,6 +2589,13 @@ static void ieee80211_mgd_probe_ap(struct ieee80211_sub_if_data *sdata, 
		goto out;

	}



	if (sdata->local->suspending) {

		/* reschedule after resume */

		mutex_unlock(&sdata->local->mtx);

		ieee80211_reset_ap_probe(sdata);

		goto out;

	}



	if (beacon) {

		mlme_dbg_ratelimited(sdata,

				     "detected beacon loss from AP (missed %d beacons) - probing\n",

net/mac80211/pm.c

+4 −0
Original line number Diff line number Diff line
@@ -27,6 +27,9 @@ int __ieee80211_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan) 
	if (!local->open_count)

		goto suspend;



	local->suspending = true;

	mb(); /* make suspending visible before any cancellation */



	ieee80211_scan_cancel(local);



	ieee80211_dfs_cac_cancel(local);
@@ -176,6 +179,7 @@ int __ieee80211_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan) 
	/* need suspended to be visible before quiescing is false */

	barrier();

	local->quiescing = false;

	local->suspending = false;



	return 0;

}