linux/net/mac80211/pm.c
Johannes Berg b20d34c458 mac80211: fix station entry leak/warning while suspending
Since Stanislaw's patches, when suspending while connected,
cfg80211 will disconnect. This causes the AP station to be
removed, which uses call_rcu() to clean up. Due to needing
process context, this queues a work struct on the mac80211
workqueue. This will warn and fail when already suspended,
which can happen if the rcu call doesn't happen quickly.

To fix this, replace the synchronize_net() which is really
just synchronize_rcu_expedited() with rcu_barrier(), which
unlike synchronize_rcu() waits until RCU callback have run
and thus avoids this issue.

In theory, this can even happen without Stanislaw's change
to disconnect on suspend since userspace might disconnect
just before suspending, though then it's unlikely that the
call_rcu() will be delayed long enough.

Cc: stable@vger.kernel.org [3.7+]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2013-04-17 11:40:39 +02:00

142 lines
3.4 KiB
C

#include <net/mac80211.h>
#include <net/rtnetlink.h>
#include "ieee80211_i.h"
#include "mesh.h"
#include "driver-ops.h"
#include "led.h"
int __ieee80211_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_sub_if_data *sdata;
struct sta_info *sta;
if (!local->open_count)
goto suspend;
ieee80211_scan_cancel(local);
ieee80211_dfs_cac_cancel(local);
ieee80211_roc_purge(local, NULL);
ieee80211_del_virtual_monitor(local);
if (hw->flags & IEEE80211_HW_AMPDU_AGGREGATION) {
mutex_lock(&local->sta_mtx);
list_for_each_entry(sta, &local->sta_list, list) {
set_sta_flag(sta, WLAN_STA_BLOCK_BA);
ieee80211_sta_tear_down_BA_sessions(
sta, AGG_STOP_LOCAL_REQUEST);
}
mutex_unlock(&local->sta_mtx);
}
ieee80211_stop_queues_by_reason(hw,
IEEE80211_MAX_QUEUE_MAP,
IEEE80211_QUEUE_STOP_REASON_SUSPEND);
/* flush out all packets and station cleanup call_rcu()s */
rcu_barrier();
ieee80211_flush_queues(local, NULL);
local->quiescing = true;
/* make quiescing visible to timers everywhere */
mb();
flush_workqueue(local->workqueue);
/* Don't try to run timers while suspended. */
del_timer_sync(&local->sta_cleanup);
/*
* Note that this particular timer doesn't need to be
* restarted at resume.
*/
cancel_work_sync(&local->dynamic_ps_enable_work);
del_timer_sync(&local->dynamic_ps_timer);
local->wowlan = wowlan && local->open_count;
if (local->wowlan) {
int err = drv_suspend(local, wowlan);
if (err < 0) {
local->quiescing = false;
local->wowlan = false;
if (hw->flags & IEEE80211_HW_AMPDU_AGGREGATION) {
mutex_lock(&local->sta_mtx);
list_for_each_entry(sta,
&local->sta_list, list) {
clear_sta_flag(sta, WLAN_STA_BLOCK_BA);
}
mutex_unlock(&local->sta_mtx);
}
ieee80211_wake_queues_by_reason(hw,
IEEE80211_MAX_QUEUE_MAP,
IEEE80211_QUEUE_STOP_REASON_SUSPEND);
return err;
} else if (err > 0) {
WARN_ON(err != 1);
return err;
} else {
goto suspend;
}
}
/* tear down aggregation sessions and remove STAs */
mutex_lock(&local->sta_mtx);
list_for_each_entry(sta, &local->sta_list, list) {
if (sta->uploaded) {
enum ieee80211_sta_state state;
state = sta->sta_state;
for (; state > IEEE80211_STA_NOTEXIST; state--)
WARN_ON(drv_sta_state(local, sta->sdata, sta,
state, state - 1));
}
}
mutex_unlock(&local->sta_mtx);
/* remove all interfaces */
list_for_each_entry(sdata, &local->interfaces, list) {
if (!ieee80211_sdata_running(sdata))
continue;
drv_remove_interface(local, sdata);
}
/*
* We disconnected on all interfaces before suspend, all channel
* contexts should be released.
*/
WARN_ON(!list_empty(&local->chanctx_list));
/* stop hardware - this must stop RX */
if (local->open_count)
ieee80211_stop_device(local);
suspend:
local->suspended = true;
/* need suspended to be visible before quiescing is false */
barrier();
local->quiescing = false;
return 0;
}
/*
* __ieee80211_resume() is a static inline which just calls
* ieee80211_reconfig(), which is also needed for hardware
* hang/firmware failure/etc. recovery.
*/
void ieee80211_report_wowlan_wakeup(struct ieee80211_vif *vif,
struct cfg80211_wowlan_wakeup *wakeup,
gfp_t gfp)
{
struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
cfg80211_report_wowlan_wakeup(&sdata->wdev, wakeup, gfp);
}
EXPORT_SYMBOL(ieee80211_report_wowlan_wakeup);