On Sat, 2010-07-17 at 21:29 +0200, Johannes Berg wrote: > Maybe we should hold the mutex around the debugfs stuff as well? Then > tools could even access that race-free, and we can simplify the code by > having an "out_unlock" label. 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 both in sysfs and cfg80211 device list. Signed-off-by: Maxime Bizon <mbizon@xxxxxxxxxx> --- net/wireless/core.c | 14 ++++++++------ 1 files changed, 8 insertions(+), 6 deletions(-) diff --git a/net/wireless/core.c b/net/wireless/core.c index 6ac70c1..fd164db 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -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: +out_rm_dev: device_del(&rdev->wiphy.dev); + +out_unlock: + mutex_unlock(&cfg80211_mutex); return res; } EXPORT_SYMBOL(wiphy_register); -- 1.7.1 -- Maxime -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
