Re: [PATCH] clock-vmstate: Add missing END_OF_LIST

[Peter Maydell]

On Tue, 11 Jan 2022 at 10:19, Dr. David Alan Gilbert (git)
<dgilbert@redhat.com> wrote:
>
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>
> Add the missing VMSTATE_END_OF_LIST to vmstate_muldiv
>
> Fixes: 99abcbc7600 ("clock: Provide builtin multiplier/divider")
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>  hw/core/clock-vmstate.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/hw/core/clock-vmstate.c b/hw/core/clock-vmstate.c
> index 9d9174ffbd..7eccb6d4ea 100644
> --- a/hw/core/clock-vmstate.c
> +++ b/hw/core/clock-vmstate.c
> @@ -44,6 +44,7 @@ const VMStateDescription vmstate_muldiv = {
>      .fields = (VMStateField[]) {
>          VMSTATE_UINT32(multiplier, Clock),
>          VMSTATE_UINT32(divider, Clock),
> +        VMSTATE_END_OF_LIST()
>      },
>  };

Oops :-(

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

We could maybe make this kind of bug more likely to be detected by
instead of having the terminator be an "all zeros" VMStateField,
having it check both for name == NULL and for a magic number in the
VMStateFlags field. That way (assuming something in "make check"
causes us to do a scan through every registered vmstate struct)
forgetting the terminator will be likely to cause us to crash or hang
rather than finding some 0 data and thinking that's the
terminator.

thanks
-- PMM