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Commit 5a652052 authored by Maxime Bizon's avatar Maxime Bizon Committed by John W. Linville
Browse files

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: default avatarMaxime Bizon <mbizon@freebox.fr>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent acd82aa8

net/wireless/core.c

+8 −6
Original line number Diff line number Diff line
@@ -472,24 +472,22 @@ int wiphy_register(struct wiphy *wiphy) 
	/* 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 @@ int wiphy_register(struct wiphy *wiphy) 
	}



	cfg80211_debugfs_rdev_add(rdev);

	mutex_unlock(&cfg80211_mutex);



	return 0;



out_rm_dev:

	device_del(&rdev->wiphy.dev);



out_unlock:

	mutex_unlock(&cfg80211_mutex);

	return res;

}

EXPORT_SYMBOL(wiphy_register);