Re: [PATCH] genetlink: make netns aware

On Thu, 2009-06-18 at 13:17 +0200, Johannes Berg wrote:

This makes generic netlink network namespace aware.

Please drop this patch, it has a deadlock bug.

+int genlmsg_multicast(struct sk_buff *skb, u32 pid,
+		      unsigned int group, gfp_t flags)
+{
+	int ret;
+
+	if (flags & GFP_ATOMIC) {
+		rcu_read_lock();
+		ret = genlmsg_mcast(skb, pid, group, flags);
+		rcu_read_unlock();
+	} else {
+		rtnl_lock();
+		ret = genlmsg_mcast(skb, pid, group, flags);
+		rtnl_unlock();
+	}
+
+	return ret;
+}

It used to be possible to call genlmsg_multicast() under rtnl, which
will now obviously deadlock unless you also make it GFP_ATOMIC... I'm
inclined to always use RCU here to solve that, comments?

johannes