From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: DMA from stack in virtio_net and virtio_console
Date: Sun, 26 Jun 2016 05:06:19 +0300
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To: Andy Lutomirski <luto@amacapital.net>
Cc: Amit Shah <amit.shah@redhat.com>, Network Development <netdev@vger.kernel.org>, Alex Williamson <alex.williamson@hp.com>, Linux Virtualization <virtualization@lists.linux-foundation.org>
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On Fri, Jun 24, 2016 at 06:45:50PM -0700, Andy Lutomirski wrote:
> virtio_net does DMA on the stack when it calls sg_init_one in
> virtio_set_queues, virtnet_vlan_rx_add_vid, and
> virtnet_vlan_rx_kill_vid.  Michael, I think these are examples we
> missed somehow when fixing these issues earlier on.
> 
> virtio_console does it here:
> 
> sg_init_one(sg, &cpkt, sizeof(cpkt));
> 
> This will cause problems on some architectures (Xen at the very least,
> and it'll cause more subtle problems on other architectures if they
> start using the DMA API), and it will blow up horribly with virtually
> mapped stacks.
> 
> Could you fix these, please?
> 
> Thanks,
> Andy

Will do, thanks for the report.

-- 
MST