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Commit 9120d94e authored by Luciano Coelho's avatar Luciano Coelho Committed by Johannes Berg
Browse files

mac80211: handle potential race between suspend and scan completion 



If suspend starts while ieee80211_scan_completed() is running, between
the point where SCAN_COMPLETED is set and the work is queued,
ieee80211_scan_cancel() will not catch the work and we may finish
suspending before the work is actually executed, leaving the scan
running while suspended.

To fix this race, queue the scan work during resume if the
SCAN_COMPLETED flag is set and flush it immediately.

Signed-off-by: default avatarLuciano Coelho <luciano.coelho@intel.com>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 225b8189

net/mac80211/ieee80211_i.h

+2 −1
Original line number Diff line number Diff line
@@ -1752,7 +1752,8 @@ static inline int __ieee80211_resume(struct ieee80211_hw *hw) 
{

	struct ieee80211_local *local = hw_to_local(hw);



	WARN(test_bit(SCAN_HW_SCANNING, &local->scanning),

	WARN(test_bit(SCAN_HW_SCANNING, &local->scanning) &&

	     !test_bit(SCAN_COMPLETED, &local->scanning),

		"%s: resume with hardware scan still in progress\n",

		wiphy_name(hw->wiphy));

net/mac80211/util.c

+12 −0
Original line number Diff line number Diff line
@@ -2060,6 +2060,18 @@ int ieee80211_reconfig(struct ieee80211_local *local) 
	mb();

	local->resuming = false;



	/* It's possible that we don't handle the scan completion in

	 * time during suspend, so if it's still marked as completed

	 * here, queue the work and flush it to clean things up.

	 * Instead of calling the worker function directly here, we

	 * really queue it to avoid potential races with other flows

	 * scheduling the same work.

	 */

	if (test_bit(SCAN_COMPLETED, &local->scanning)) {

		ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);

		flush_delayed_work(&local->scan_work);

	}



	if (local->open_count && !reconfig_due_to_wowlan)

		drv_reconfig_complete(local, IEEE80211_RECONFIG_TYPE_SUSPEND);