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

From: Amit Shah
Date: Wed Feb 01 2017 - 08:47:21 EST


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