@@ -59,15 +59,19 @@ struct rtnl_link {
};
static DEFINE_MUTEX(rtnl_mutex);
+static struct thread_info *rtnl_owner;
void rtnl_lock(void)
{
+ BUG_ON(rtnl_owner == current_thread_info());
mutex_lock(&rtnl_mutex);
+ rtnl_owner = current_thread_info();
}
EXPORT_SYMBOL(rtnl_lock);
void __rtnl_unlock(void)
{
+ rtnl_owner = NULL;
mutex_unlock(&rtnl_mutex);
}
@@ -80,13 +84,17 @@ EXPORT_SYMBOL(rtnl_unlock);
int rtnl_trylock(void)
{
- return mutex_trylock(&rtnl_mutex);
+ int ret = mutex_trylock(&rtnl_mutex);
+
+ if (ret)
+ rtnl_owner = current_thread_info();
+ return ret;
}
EXPORT_SYMBOL(rtnl_trylock);
int rtnl_is_locked(void)
{
- return mutex_is_locked(&rtnl_mutex);
+ return mutex_is_locked(&rtnl_mutex) && rtnl_owner == current_thread_info();
}
EXPORT_SYMBOL(rtnl_is_locked);
@@ -850,6 +858,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
struct nlattr *attr, *af_spec;
struct rtnl_af_ops *af_ops;
+ ASSERT_RTNL();
nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ifm), flags);
if (nlh == NULL)
return -EMSGSIZE;
@@ -1003,10 +1012,12 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
struct net_device *dev;
struct hlist_head *head;
struct hlist_node *node;
+ int rtnl_was_locked = rtnl_is_locked();
s_h = cb->args[0];
s_idx = cb->args[1];
-
+ if (!rtnl_was_locked)
+ rtnl_lock();
rcu_read_lock();
for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
idx = 0;
@@ -1025,6 +1036,8 @@ cont:
}
out:
rcu_read_unlock();
+ if (!rtnl_was_locked)
+ rtnl_unlock();
cb->args[1] = idx;
cb->args[0] = h;
Commit e67f88dd12f610 (net: dont hold rtnl mutex during netlink dump callbacks) added a problem in rtnl_fill_ifinfo() not being always called with RTNL held, which is racy. 1) This patch extends rtnl_mutex helper functions so that : rtnl_lock() is able to BUG_ON() if recursively called. [This was only provided if LOCKDEP was on] rtnl_is_locked() is able to check if current thread owns rtnl_mutex [ASSERT_RTNL() gets this added feature too] 2) Add one ASSERT_RTNL() in rtnl_fill_ifinfo() 3) Make sure rtnl is held in rtnl_dump_ifinfo() Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> --- net/core/rtnetlink.c | 19 ++++++++++++++++--- 1 files changed, 16 insertions(+), 3 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html