cfg80211: fix locking regression in monitor channel tracking
Michal's monitor channel tracking introduce a locking problem
as it locked the rdev lock inside the netdev notifier which
isn't allowed as we might already hold it if we get there by
removing an interface that is up.
Fix this by relying only on the RTNL to protect the interface
counters, the RTNL is always held in these code paths anyway.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 81fef3d..377dc39 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -13,6 +13,7 @@
#include <linux/debugfs.h>
#include <linux/rfkill.h>
#include <linux/workqueue.h>
+#include <linux/rtnetlink.h>
#include <net/genetlink.h>
#include <net/cfg80211.h>
#include "reg.h"
@@ -56,6 +57,7 @@
u32 ap_beacons_nlpid;
+ /* protected by RTNL only */
int num_running_ifaces;
int num_running_monitor_ifaces;
@@ -205,7 +207,7 @@
static inline bool cfg80211_has_monitors_only(struct cfg80211_registered_device *rdev)
{
- ASSERT_RDEV_LOCK(rdev);
+ ASSERT_RTNL();
return rdev->num_running_ifaces == rdev->num_running_monitor_ifaces &&
rdev->num_running_ifaces > 0;