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).
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