cfg80211: fix race between sysfs and cfg80211
device_add() is called before adding the phy to the cfg80211 device
list.
So if a userspace program uses sysfs uevents to detect new phy
devices, and queries nl80211 to get phy info, it can get ENODEV even
though the phy exists in sysfs.
An easy workaround is to hold the cfg80211 mutex until the phy is
present in sysfs/cfg80211/debugfs.
Signed-off-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 47fcfd0..f65c649 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -472,24 +472,22 @@
/* check and set up bitrates */
ieee80211_set_bitrate_flags(wiphy);
+ mutex_lock(&cfg80211_mutex);
+
res = device_add(&rdev->wiphy.dev);
if (res)
- return res;
+ goto out_unlock;
res = rfkill_register(rdev->rfkill);
if (res)
goto out_rm_dev;
- mutex_lock(&cfg80211_mutex);
-
/* set up regulatory info */
wiphy_update_regulatory(wiphy, NL80211_REGDOM_SET_BY_CORE);
list_add_rcu(&rdev->list, &cfg80211_rdev_list);
cfg80211_rdev_list_generation++;
- mutex_unlock(&cfg80211_mutex);
-
/* add to debugfs */
rdev->wiphy.debugfsdir =
debugfs_create_dir(wiphy_name(&rdev->wiphy),
@@ -509,11 +507,15 @@
}
cfg80211_debugfs_rdev_add(rdev);
+ mutex_unlock(&cfg80211_mutex);
return 0;
- out_rm_dev:
+out_rm_dev:
device_del(&rdev->wiphy.dev);
+
+out_unlock:
+ mutex_unlock(&cfg80211_mutex);
return res;
}
EXPORT_SYMBOL(wiphy_register);