diff options
| author | Johannes Berg <johannes@sipsolutions.net> | 2009-03-24 09:35:46 +0100 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2009-03-27 20:13:20 -0400 |
| commit | 4bbf4d56583dd52c429d88f43cb614bdbe5deea6 (patch) | |
| tree | 7a3f902a08820342254e0d67607fe870b02620b3 /net/wireless/core.c | |
| parent | 3832c287f11ba001bbe48e9be8c59cb9f71f6b43 (diff) | |
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/core.c')
| -rw-r--r-- | net/wireless/core.c | 30 |
1 files changed, 10 insertions, 20 deletions
diff --git a/net/wireless/core.c b/net/wireless/core.c index 17fe3904974..d1f556535f6 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -87,7 +87,7 @@ struct wiphy *wiphy_idx_to_wiphy(int wiphy_idx) } /* requires cfg80211_mutex to be held! */ -static struct cfg80211_registered_device * +struct cfg80211_registered_device * __cfg80211_drv_from_info(struct genl_info *info) { int ifindex; @@ -176,13 +176,14 @@ void cfg80211_put_dev(struct cfg80211_registered_device *drv) mutex_unlock(&drv->mtx); } +/* requires cfg80211_mutex to be held */ int cfg80211_dev_rename(struct cfg80211_registered_device *rdev, char *newname) { struct cfg80211_registered_device *drv; int wiphy_idx, taken = -1, result, digits; - mutex_lock(&cfg80211_mutex); + assert_cfg80211_lock(); /* prohibit calling the thing phy%d when %d is not its number */ sscanf(newname, PHY_NAME "%d%n", &wiphy_idx, &taken); @@ -195,30 +196,23 @@ int cfg80211_dev_rename(struct cfg80211_registered_device *rdev, * deny the name if it is phy<idx> where <idx> is printed * without leading zeroes. taken == strlen(newname) here */ - result = -EINVAL; if (taken == strlen(PHY_NAME) + digits) - goto out_unlock; + return -EINVAL; } /* Ignore nop renames */ - result = 0; if (strcmp(newname, dev_name(&rdev->wiphy.dev)) == 0) - goto out_unlock; + return 0; /* Ensure another device does not already have this name. */ - list_for_each_entry(drv, &cfg80211_drv_list, list) { - result = -EINVAL; + list_for_each_entry(drv, &cfg80211_drv_list, list) if (strcmp(newname, dev_name(&drv->wiphy.dev)) == 0) - goto out_unlock; - } + return -EINVAL; - /* this will only check for collisions in sysfs - * which is not even always compiled in. - */ result = device_rename(&rdev->wiphy.dev, newname); if (result) - goto out_unlock; + return result; if (rdev->wiphy.debugfsdir && !debugfs_rename(rdev->wiphy.debugfsdir->d_parent, @@ -228,13 +222,9 @@ int cfg80211_dev_rename(struct cfg80211_registered_device *rdev, printk(KERN_ERR "cfg80211: failed to rename debugfs dir to %s!\n", newname); - result = 0; -out_unlock: - mutex_unlock(&cfg80211_mutex); - if (result == 0) - nl80211_notify_dev_rename(rdev); + nl80211_notify_dev_rename(rdev); - return result; + return 0; } /* exported functions */ |