cfg80211: fix sysfs registration race

My locking rework/race fixes caused a regression in the
registration, causing uevent notifications for wireless
devices before the device is really fully registered and
available in nl80211.

Fix this by moving the device_add() under rtnl and move
the rfkill to afterwards (it can't be under rtnl.)

Reported-and-tested-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 13 insertions, 8 deletions

diff --git a/net/wireless/core.c b/net/wireless/core.c
index 67153964aad2..fe8d4f2be49b 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -566,18 +566,13 @@ int wiphy_register(struct wiphy *wiphy)
         /* check and set up bitrates */
         ieee80211_set_bitrate_flags(wiphy);
 
-
+        rtnl_lock();
         res = device_add(&rdev->wiphy.dev);
-        if (res)
-                return res;
-
-        res = rfkill_register(rdev->rfkill);
         if (res) {
-                device_del(&rdev->wiphy.dev);
+                rtnl_unlock();
                 return res;
         }
 
-        rtnl_lock();
         /* set up regulatory info */
         wiphy_regulatory_register(wiphy);
 
@@ -606,6 +601,15 @@ int wiphy_register(struct wiphy *wiphy)
 
         rdev->wiphy.registered = true;
         rtnl_unlock();
+
+        res = rfkill_register(rdev->rfkill);
+        if (res) {
+                rfkill_destroy(rdev->rfkill);
+                rdev->rfkill = NULL;
+                wiphy_unregister(&rdev->wiphy);
+                return res;
+        }
+
         return 0;
 }
 EXPORT_SYMBOL(wiphy_register);
@@ -640,7 +644,8 @@ void wiphy_unregister(struct wiphy *wiphy)
                 rtnl_unlock();
                 __count == 0; }));
 
-        rfkill_unregister(rdev->rfkill);
+        if (rdev->rfkill)
+                rfkill_unregister(rdev->rfkill);
 
         rtnl_lock();
         rdev->wiphy.registered = false;