[PATCH] coresight: etm4x: Fix PID tracing when perf is run in an init PID namespace

[Suzuki K Poulose]

On 25/09/2024 14:13, Julien Meunier wrote:
> The previous implementation limited the tracing capabilities when perf
> was run in the init PID namespace, making it impossible to trace
> applications in non-init PID namespaces.
> 
> This update improves the tracing process by verifying the event owner.
> This allows us to determine whether the user has the necessary
> permissions to trace the application.
> 
> Cc: stable at vger.kernel.org
> Fixes: aab473867fed ("coresight: etm4x: Don't trace PID for non-root PID namespace")
> Signed-off-by: Julien Meunier <julien.meunier at nokia.com>

Thanks for the fix, I will queue this for v6.13

Suzuki


> ---
>   drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index bf01f01964cf..8365307b1aec 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -695,7 +695,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
>   
>   	/* Only trace contextID when runs in root PID namespace */
>   	if ((attr->config & BIT(ETM_OPT_CTXTID)) &&
> -	    task_is_in_init_pid_ns(current))
> +	    task_is_in_init_pid_ns(event->owner))
>   		/* bit[6], Context ID tracing bit */
>   		config->cfg |= TRCCONFIGR_CID;
>   
> @@ -710,7 +710,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
>   			goto out;
>   		}
>   		/* Only trace virtual contextID when runs in root PID namespace */
> -		if (task_is_in_init_pid_ns(current))
> +		if (task_is_in_init_pid_ns(event->owner))
>   			config->cfg |= TRCCONFIGR_VMID | TRCCONFIGR_VMIDOPT;
>   	}
>