Re: [RFC][PATCH 2/9] deadlock prevention core

From: David Miller
Date: Sun Aug 13 2006 - 19:49:47 EST

From: Daniel Phillips <phillips@xxxxxxxxxx>
Date: Sun, 13 Aug 2006 14:22:31 -0700

> David Miller wrote:
> > The reason is that there is no refcounting performed on these devices
> > when they are attached to the skb, for performance reasons, and thus
> > the device can be downed, the module for it removed, etc. long before
> > the skb is freed up.
> The virtual block device can refcount the network device on virtual
> device create and un-refcount on virtual device delete.

What if the packet is originally received on the device in question,
and then gets redirected to another device by a packet scheduler
traffic classifier action or a netfilter rule?

It is necessary to handle the case where the device changes on the
skb, and the skb gets freed up in a context and assosciation different
from when the skb was allocated (for example, different from the
device attached to the virtual block device).
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at