Re: [PATCH] virtio-console: avoid DMA from stack

From: Michael S. Tsirkin
Date: Wed Mar 01 2017 - 16:35:21 EST


On Wed, Mar 01, 2017 at 12:01:10PM -0800, Omar Sandoval wrote:
> On Wed, Feb 01, 2017 at 07:17:12PM +0530, Amit Shah wrote:
> > On (Wed) 01 Feb 2017 [00:02:27], Omar Sandoval wrote:
> > > From: Omar Sandoval <osandov@xxxxxx>
> > >
> > > put_chars() stuffs the buffer it gets into an sg, but that buffer may be
> > > on the stack. This breaks with CONFIG_VMAP_STACK=y (for me, it
> > > manifested as printks getting turned into NUL bytes).
> >
> > Seems reasonable. I wonder since all implementations of hvc do a
> > memcpy, if we can abstract it - but that'll need some work.
> >
> > Reviewed-by: Amit Shah <amit.shah@xxxxxxxxxx>
> >
> > Michael, please add to the virtio queue.
> >
> > Amit
>
> Hi, Michael,
>
> I don't see this in Linus' master or in your git tree, is it going to go
> in for -rc1?
>
> Thanks.

Yes.