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Date: Wed, 27 Jul 2011 11:43:44 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20110727084344.GE15762@redhat.com>
References: <cover.1311755243.git.amit.shah@redhat.com>
	<3c8905c75dbc9973eb9f0dd0823a0989ee2e12d1.1311755243.git.amit.shah@redhat.com>
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In-Reply-To: <3c8905c75dbc9973eb9f0dd0823a0989ee2e12d1.1311755243.git.amit.shah@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 3/4] virtio-net: Fix potential
	use-after-free
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To: Amit Shah <amit.shah@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, qemu list <qemu-devel@nongnu.org>, Markus Armbruster <armbru@redhat.com>

On Wed, Jul 27, 2011 at 02:00:31PM +0530, Amit Shah wrote:
> virtio_cleanup() will remove the VirtIONet struct that gets allocated
> via virtio_common_init().  Ensure we don't dereference the structure
> after calling the cleanup function.
> 
> Signed-off-by: Amit Shah <amit.shah@redhat.com>

I see. It's not a use after free but will be once
you make virtio_cleanup free the vdev?

> ---
>  hw/virtio-net.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/hw/virtio-net.c b/hw/virtio-net.c
> index a32cc01..3f10391 100644
> --- a/hw/virtio-net.c
> +++ b/hw/virtio-net.c
> @@ -1073,6 +1073,6 @@ void virtio_net_exit(VirtIODevice *vdev)
>          qemu_bh_delete(n->tx_bh);
>      }
>  
> -    virtio_cleanup(&n->vdev);
>      qemu_del_vlan_client(&n->nic->nc);
> +    virtio_cleanup(&n->vdev);
>  }
> -- 
> 1.7.6