mac80211: disable beacons before removing the associated interface

When downing interfaces, it's a good idea to tell the driver to
stop sending beacons; that way the driver doesn't need special
code in ops->remove_interface() when it should already handle the
case in bss_info_changed().

This fixes a potential crash with at least ath5k since the vif
pointer will be nullified while beacon interrupts are still active.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 16 insertions, 1 deletions

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 6c655b6547fb..6614d4ff273d 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -522,6 +522,16 @@ static int ieee80211_stop(struct net_device *dev)
                                 ieee80211_scan_completed(&local->hw, true);
                 }
 
+                /*
+                 * Disable beaconing for AP and mesh, IBSS can't
+                 * still be joined to a network at this point.
+                 */
+                if (sdata->vif.type == NL80211_IFTYPE_AP ||
+                    sdata->vif.type == NL80211_IFTYPE_MESH_POINT) {
+                        ieee80211_bss_info_change_notify(sdata,
+                                BSS_CHANGED_BEACON_ENABLED);
+                }
+
                 conf.vif = &sdata->vif;
                 conf.type = sdata->vif.type;
                 conf.mac_addr = dev->dev_addr;
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 9dd8d25611e0..5e76dd1daf71 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -198,7 +198,8 @@ void ieee80211_bss_info_change_notify(struct ieee80211_sub_if_data *sdata,
         }
 
         if (changed & BSS_CHANGED_BEACON_ENABLED) {
-                if (test_bit(SCAN_SW_SCANNING, &local->scanning)) {
+                if (local->quiescing || !netif_running(sdata->dev) ||
+                    test_bit(SCAN_SW_SCANNING, &local->scanning)) {
                         sdata->vif.bss_conf.enable_beacon = false;
                 } else {
                         /*
diff --git a/net/mac80211/pm.c b/net/mac80211/pm.c
index 5e3d476972f9..3320f7daaf25 100644
--- a/net/mac80211/pm.c
+++ b/net/mac80211/pm.c
@@ -96,6 +96,10 @@ int __ieee80211_suspend(struct ieee80211_hw *hw)
                 if (!netif_running(sdata->dev))
                         continue;
 
+                /* disable beaconing */
+                ieee80211_bss_info_change_notify(sdata,
+                        BSS_CHANGED_BEACON_ENABLED);
+
                 conf.vif = &sdata->vif;
                 conf.type = sdata->vif.type;
                 conf.mac_addr = sdata->dev->dev_addr;