Re: [PATCH 6/8] packet, clang-tidy: Packet pool buffers are not NULL

[Laurent Vivier <lvivier@redhat.com>]

On 5/11/26 12:03, David Gibson wrote:
> struct pool always needs a non-NULL buf field: it points either to the
> actual memory used to store packets, or for vhost-user to the vhost user
> memory structure which will contain the packets.  We set this pointer
> when we initialise the pool.  However, clang-tidy (as of 22.1.4, at least)
> doesn't realise this in packet_check_range(), causing UB warnings due to
> the subtraction of ptr and p->buf.
> 
> Clue it in with an assert().
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

Reviewed-by: Laurent Vivier <lvivier@redhat.com>

> ---
>   packet.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/packet.c b/packet.c
> index 1cb74b74..7a347be6 100644
> --- a/packet.c
> +++ b/packet.c
> @@ -51,6 +51,8 @@ static int packet_check_range(const struct pool *p, const char *ptr, size_t len,
>   {
>   	struct vdev_memory *memory;
>   
> +	assert(p->buf);
> +
>   	if (len > PACKET_MAX_LEN) {
>   		debug("packet range length %zu (max %zu), %s:%i",
>   		      len, PACKET_MAX_LEN, func, line);