Re: 2.6.7-rc3: unregister_netdevice: waiting for tun0 to become free. Usage count = 1

["David S. Miller" <davem@redhat.com>]

On Wed, 16 Jun 2004 23:37:31 +0400
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> wrote:

> Anyway, the comment remains damn true and the place is still
> bug. It makes sense to think about waiting for at least one quiescent
> state after detaching the stale device from dst and real dev_put() it.
> Reference to RCU is not occasional, the job looks natural for it.

It seems a simple synchronize_kernel() would clear all the
crap no?

===== net/core/dst.c 1.18 vs edited =====
--- 1.18/net/core/dst.c	2004-06-16 10:26:56 -07:00
+++ edited/net/core/dst.c	2004-06-16 13:10:37 -07:00
@@ -243,6 +243,8 @@
 			dst->ops->ifdown(dst, unregister);
 	} while ((dst = dst->child) && dst->flags & DST_NOHASH &&
 		 dst->dev == dev);
+
+	synchronize_kernel();
 }
 
 static int dst_dev_event(struct notifier_block *this, unsigned long event, void *ptr)