Re: [PATCH net-next v2] gve: enhance no queue page list detection

[Bailey Forrest]

On Mon, Feb 14, 2022 at 9:52 PM Haiyue Wang <haiyue.wang@xxxxxxxxx> wrote:
>
> The commit
> a5886ef4f4bf ("gve: Introduce per netdev `enum gve_queue_format`")
> introduces three queue format type, only GVE_GQI_QPL_FORMAT queue has
> page list. So it should use the queue page list number to detect the
> zero size queue page list. Correct the design logic.
>
> Using the 'queue_format == GVE_GQI_RDA_FORMAT' may lead to request zero
> sized memory allocation, like if the queue format is GVE_DQO_RDA_FORMAT.
>
> The kernel memory subsystem will return ZERO_SIZE_PTR, which is not NULL
> address, so the driver can run successfully. Also the code still checks
> the queue page list number firstly, then accesses the allocated memory,
> so zero number queue page list allocation will not lead to access fault.
>
> Signed-off-by: Haiyue Wang <haiyue.wang@xxxxxxxxx>

Reviewed-by: Bailey Forrest <bcf@xxxxxxxxxx>