Re: [PATCH] perf/arm-cmn: Validate cycles events fully

[Ilkka Koskinen]

On Mon, 3 Apr 2023, Robin Murphy wrote:
> DTC cycle count events don't have anything to validate or initialise in
> themselves, but we should not forget to still validate their whole group
> context. Otherwise, we may fail to correctly reject a contrived group
> containing an impossible number of cycles events.
>
> Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>

Looks good to me and works as expected.

Cheers, Ilkka

> ---
> drivers/perf/arm-cmn.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
> index 367d41c5d983..45819528facb 100644
> --- a/drivers/perf/arm-cmn.c
> +++ b/drivers/perf/arm-cmn.c
> @@ -1558,7 +1558,7 @@ static int arm_cmn_event_init(struct perf_event *event)
> 	type = CMN_EVENT_TYPE(event);
> 	/* DTC events (i.e. cycles) already have everything they need */
> 	if (type == CMN_TYPE_DTC)
> -		return 0;
> +		return arm_cmn_validate_group(cmn, event);
>
> 	eventid = CMN_EVENT_EVENTID(event);
> 	/* For watchpoints we need the actual XP node here */
> --
> 2.39.2.101.g768bb238c484.dirty
>
>
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