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authorJohannes Berg <johannes@sipsolutions.net>2009-03-24 09:35:46 +0100
committerJohn W. Linville <linville@tuxdriver.com>2009-03-27 20:13:20 -0400
commit4bbf4d56583dd52c429d88f43cb614bdbe5deea6 (patch)
tree7a3f902a08820342254e0d67607fe870b02620b3 /net/wireless/nl80211.c
parent3832c287f11ba001bbe48e9be8c59cb9f71f6b43 (diff)
downloadlinux-4bbf4d56583dd52c429d88f43cb614bdbe5deea6.tar.gz
cfg80211: fix locking in nl80211_set_wiphy
Luis reports that there's a circular locking dependency; this is because cfg80211_dev_rename() will acquire the cfg80211_mutex while the device mutex is held, while this normally is done the other way around. The solution is to open-code the device-getting in nl80211_set_wiphy and require holding the mutex around cfg80211_dev_rename rather than acquiring it within. Also fix a bug -- rtnl locking is expected by drivers so we need to provide it. Reported-by: Luis R. Rodriguez <lrodriguez@atheros.com> Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net/wireless/nl80211.c')
-rw-r--r--net/wireless/nl80211.c28
1 files changed, 20 insertions, 8 deletions
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 8808431bd58..353e1a4ece8 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -366,16 +366,26 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
int result = 0, rem_txq_params = 0;
struct nlattr *nl_txq_params;
- rdev = cfg80211_get_dev_from_info(info);
- if (IS_ERR(rdev))
- return PTR_ERR(rdev);
+ rtnl_lock();
+
+ mutex_lock(&cfg80211_mutex);
+
+ rdev = __cfg80211_drv_from_info(info);
+ if (IS_ERR(rdev)) {
+ result = PTR_ERR(rdev);
+ goto unlock;
+ }
- if (info->attrs[NL80211_ATTR_WIPHY_NAME]) {
+ mutex_lock(&rdev->mtx);
+
+ if (info->attrs[NL80211_ATTR_WIPHY_NAME])
result = cfg80211_dev_rename(
rdev, nla_data(info->attrs[NL80211_ATTR_WIPHY_NAME]));
- if (result)
- goto bad_res;
- }
+
+ mutex_unlock(&cfg80211_mutex);
+
+ if (result)
+ goto bad_res;
if (info->attrs[NL80211_ATTR_WIPHY_TXQ_PARAMS]) {
struct ieee80211_txq_params txq_params;
@@ -471,7 +481,9 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
bad_res:
- cfg80211_put_dev(rdev);
+ mutex_unlock(&rdev->mtx);
+ unlock:
+ rtnl_unlock();
return result;
}