2013-01-09 11:05:36

by Johannes Berg

Subject: [PATCH v2] regulatory: fix uevent

From: Johannes Berg <[email protected]>

The uevent callback doesn't protect its access to
last_request, which now causes a warning since
the conversion to get_last_request(). Fix this by
allowing to use RCU protection for last_request.

Signed-off-by: Johannes Berg <[email protected]>
---
net/wireless/reg.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 0b35de0..2193f62 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -140,8 +140,8 @@ static void rcu_free_regdom(const struct ieee80211_regdomain *r)

static struct regulatory_request *get_last_request(void)
{
- return rcu_dereference_protected(last_request,
- lockdep_is_held(&reg_mutex));
+ return rcu_dereference_check(last_request,
+ lockdep_is_held(&reg_mutex));
}

/* Used to queue up regulatory hints */
@@ -2250,14 +2250,21 @@ int set_regdom(const struct ieee80211_regdomain *rd)
#ifdef CONFIG_HOTPLUG
int reg_device_uevent(struct device *dev, struct kobj_uevent_env *env)
{
- struct regulatory_request *lr = get_last_request();
+ struct regulatory_request *lr;
+ u8 alpha2[2];
+ bool add = false;

+ rcu_read_lock();
+ lr = get_last_request();
if (lr && !lr->processed) {
- if (add_uevent_var(env, "COUNTRY=%c%c",
- lr->alpha2[0], lr->alpha2[1]))
- return -ENOMEM;
+ memcpy(alpha2, lr->alpha2, 2);
+ add = true;
}
+ rcu_read_unlock();

+ if (add)
+ return add_uevent_var(env, "COUNTRY=%c%c",
+ alpha2[0], alpha2[1]);
return 0;
}
#else
--
1.8.0

2013-01-09 11:19:06

by Johannes Berg

Subject: Re: [PATCH v2] regulatory: fix uevent

On Wed, 2013-01-09 at 12:06 +0100, Johannes Berg wrote:
> From: Johannes Berg <[email protected]>
>
> The uevent callback doesn't protect its access to
> last_request, which now causes a warning since
> the conversion to get_last_request(). Fix this by
> allowing to use RCU protection for last_request.

Applied.

johannes