mac80211: fix race between connection monitor & suspend
When the connection monitor timer fires right before
suspend, the following will happen:
timer fires -> monitor_work gets queued
suspend calls ieee80211_sta_quiesce
ieee80211_sta_quiesce:
- deletes timer
- cancels monitor_work synchronously, running it
[note wrong order of these steps]
monitor_work runs, re-arming the timer
later, timer fires while system should be quiesced
This causes a warning:
WARNING: at net/mac80211/util.c:540 ieee80211_can_queue_work+0x35/0x40 [mac80211]()
but is otherwise harmless. I'm not completely sure
this is the scenario Thomas stumbled across, but it
is the only way I can right now see the warning in
a scenario like the one he reported.
Reported-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index d3b408c..40db011 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2286,6 +2286,7 @@
cancel_work_sync(&ifmgd->request_smps_work);
+ cancel_work_sync(&ifmgd->monitor_work);
cancel_work_sync(&ifmgd->beacon_connection_loss_work);
if (del_timer_sync(&ifmgd->timer))
set_bit(TMR_RUNNING_TIMER, &ifmgd->timers_running);
@@ -2294,7 +2295,6 @@
if (del_timer_sync(&ifmgd->chswitch_timer))
set_bit(TMR_RUNNING_CHANSW, &ifmgd->timers_running);
- cancel_work_sync(&ifmgd->monitor_work);
/* these will just be re-established on connection */
del_timer_sync(&ifmgd->conn_mon_timer);
del_timer_sync(&ifmgd->bcn_mon_timer);