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

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

[Robin Murphy]

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@arm.com>
---
 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

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@arm.com>

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
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>

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

[Will Deacon]

On Mon, 3 Apr 2023 12:49:05 +0100, 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.
> 
> 

Applied to will (for-next/perf), thanks!

[1/1] perf/arm-cmn: Validate cycles events fully
      https://git.kernel.org/will/c/23b2fd839489

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev