[PATCH 05/10] staging: unisys: visorbus: Clarify reason for pointer check in bus_destroy()

[Greg KH]

On Wed, Feb 01, 2017 at 05:38:57PM -0500, David Kershner wrote:
> From: David Binder <david.binder at unisys.com>
> 
> Clarifies why the pointer returned from visorbus_get_device_by_id() in
> bus_destroy() is validated. The check is performed in order to be extra
> careful, for the sake of added security, that the s-Par backend is
> providing us with a valid bus/device pair.
> 
> Signed-off-by: David Binder <david.binder at unisys.com>
> Signed-off-by: David Kershner <david.kershner at unisys.com>
> Reported-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> ---
>  drivers/staging/unisys/visorbus/visorchipset.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/staging/unisys/visorbus/visorchipset.c b/drivers/staging/unisys/visorbus/visorchipset.c
> index c90ea6a..2d1b226 100644
> --- a/drivers/staging/unisys/visorbus/visorchipset.c
> +++ b/drivers/staging/unisys/visorbus/visorchipset.c
> @@ -755,6 +755,7 @@ bus_destroy(struct controlvm_message *inmsg)
>  	int err;
>  
>  	bus_info = visorbus_get_device_by_id(bus_no, BUS_ROOT_DEVICE, NULL);
> +	/* Validate that s-Par backend gave a good bus */

I don't remember what I said in my review, but this comment is pretty
useless.

I guess my point is, how could BUS_ROOT_DEVICE ever NOT be a valid
device on the bus?  What would have made it go away?

Comments like this don't make much sense, maybe my review didn't either
:)

thanks,

greg k-h