Re: [PATCH 5/9] network namespaces: async socket operations

On Fri, Sep 22, 2006 at 05:33:56PM +0200, Daniel Lezcano wrote:

Andrey Savochkin wrote:

quoted

Non-trivial part of socket namespaces: asynchronous events
should be run in proper context.

Signed-off-by: Andrey Savochkin <redacted>
---
 af_inet.c            |   10 ++++++++++
 inet_timewait_sock.c |    8 ++++++++
 tcp_timer.c          |    9 +++++++++
 3 files changed, 27 insertions(+)

--- ./net/ipv4/af_inet.c.venssock-asyn	Mon Aug 14 17:04:07 2006
+++ ./net/ipv4/af_inet.c	Tue Aug 15 13:45:44 2006

@@ -366,10 +366,17 @@ out_rcu_unlock:
 int inet_release(struct socket *sock)
 {
 	struct sock *sk = sock->sk;
+	struct net_namespace *ns, *orig_net_ns;
 
 	if (sk) {
 		long timeout;
 
+		/* Need to change context here since protocol ->close
+		 * operation may send packets.
+		 */
+		ns = get_net_ns(sk->sk_net_ns);
+		push_net_ns(ns, orig_net_ns);
+

Is it not a race condition here ? What happens if you have a packet 
incoming during the namespace context switching ?

All asynchronous operations (RX softirq, timers) should set their context
explicitly, and can't rely on the current context being the right one
(or a valid pointer at all).

	Andrey