Re: [RFC PATCH 4/8] virtio: console: Ignore port name update request if name already set

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Jul 28, 2011 at 08:05:09PM +0530, Amit Shah wrote:
> We don't allow port name changes dynamically for a port.  So any
> requests by the host to change the name are ignored.

It would be nice to check the name and if
changed, print a warning.

> 
> Before this patch, if the hypervisor sent a port name while we had one
> set already, we would leak memory equivalent to the size of the old
> name.
> 
> This scenario wasn't expected so far, but with the suspend-resume
> support, we'll send the VIRTIO_CONSOLE_PORT_READY message after restore,
> which can get us into this situation.
> 
> Signed-off-by: Amit Shah <amit.shah@redhat.com>

Memleaks are bad. So this is a bugfix we probably should have anyway?

> ---
>  drivers/char/virtio_console.c |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
> index fb68b12..3c10b10 100644
> --- a/drivers/char/virtio_console.c
> +++ b/drivers/char/virtio_console.c
> @@ -1394,6 +1394,13 @@ static void handle_control_message(struct ports_device *portdev,
>  		break;
>  	case VIRTIO_CONSOLE_PORT_NAME:
>  		/*
> +		 * If we woke up after hibernation, we can get this
> +		 * again.  Skip it in that case.
> +		 */
> +		if (port->name)
> +			break;
> +
> +		/*
>  		 * Skip the size of the header and the cpkt to get the size
>  		 * of the name that was sent
>  		 */
> -- 
> 1.7.6