cfg80211: fix race between sysfs and cfg80211 (5a652052) · Commits · 戴 / test

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>

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);

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