Re: [PATCH v1] gve: fix zero size queue page list allocation

[Jakub Kicinski]

On Mon, 14 Feb 2022 10:41:29 +0800 Haiyue Wang wrote:
> According to the two functions 'gve_num_tx/rx_qpls', only the queue with
> GVE_GQI_QPL_FORMAT format has queue page list.
> 
> 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.
> 
> Use the queue page list number to detect no QPLs, it can avoid zero size
> queue page list memory allocation.

There's no bug here, strictly speaking, the driver will function
correctly? In that case please repost without the Fixes tag and
with [PATCH net-next] in the subject.

> Fixes: a5886ef4f4bf ("gve: Introduce per netdev `enum gve_queue_format`")
> Signed-off-by: Haiyue Wang <haiyue.wang@xxxxxxxxx>