Re: [PATCH] domain: try to address Coverity pointing out a missing "break" in domain_teardown()

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

Hi Jan,

> On 1 Sep 2021, at 09:45, Jan Beulich <jbeulich@xxxxxxxx> wrote:
> 
> Commit 806448806264 ("xen/domain: Fix label position in
> domain_teardown()" has caused Coverity to report a _new_ supposedly
> un-annotated fall-through in a switch(). I find this (once again)
> puzzling; I'm having an increasingly hard time figuring what patterns
> the tool is actually after. I would have expected that the tool would
> either have spotted an issue also before this change, or not at all. Yet
> if it had spotted one before, the statistics report should have included
> an eliminated instance alongside the new one (because then the issue
> would simply have moved by a few lines).
> 
> Hence the only thing I could guess is that the treatment of comments in
> macro expansions might be subtly different. Therefore try whether
> switching the comments to the still relatively new "fallthrough" pseudo
> keyword actually helps.
> 
> Coverity-ID: 1490865
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

A grep inside Xen code show that we have occurence of:
/* fallthrough */
/* Fallthrough */
falltrough

Should we actually fix all of them ?

Anyway this can be in an other patch.

Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>

Cheers
Bertrand

> ---
> If this doesn't help, I'm afraid I'm lost as to what Coverity means us
> to do to silence the reporting.
> 
> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -401,13 +401,13 @@ static int domain_teardown(struct domain
>          */
> #define PROGRESS(x)                             \
>         d->teardown.val = PROG_ ## x;           \
> -        /* Fallthrough */                       \
> +        fallthrough;                            \
>     case PROG_ ## x
> 
> #define PROGRESS_VCPU(x)                        \
>         d->teardown.val = PROG_vcpu_ ## x;      \
>         d->teardown.vcpu = v;                   \
> -        /* Fallthrough */                       \
> +        fallthrough;                            \
>     case PROG_vcpu_ ## x:                       \
>         v = d->teardown.vcpu
> 
> 
>