Re: [PATCH v2 06/11] drivers/acpi/apei: convert seqno counter_atomic32

[Kees Cook]

On Tue, Oct 06, 2020 at 02:44:37PM -0600, Shuah Khan wrote:
> counter_atomic* is introduced to be used when a variable is used as
> a simple counter and doesn't guard object lifetimes. This clearly
> differentiates atomic_t usages that guard object lifetimes.
> 
> counter_atomic* variables will wrap around to 0 when it overflows and
> should not be used to guard resource lifetimes, device usage and
> open counts that control state changes, and pm states.
> 
> seqno is a sequence number counter for logging. This counter gets
> incremented. Unsure if there is a chance of this overflowing. It
> doesn't look like overflowing causes any problems since it is used
> to tag the log messages and nothing more.
> 
> Convert it to use counter_atomic32.
> 
> This conversion doesn't change the overflow wrap around behavior.
> 
> Acked-by: Rafael J. Wysocki <rafael@xxxxxxxxxx>
> Acked-by: Borislav Petkov <bp@xxxxxxx>
> Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>

Yup, also logging only, it seems.

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-- 
Kees Cook