Re: [PATCH] coresight: Only register perf symlink for sinks with alloc_buffer

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 30/06/2025 11:26, Yuanfang Zhang wrote:
> Ensure that etm_perf_add_symlink_sink() is only called for devices
> that implement the alloc_buffer operation. This prevents invalid
> symlink creation for dummy sinks that do not implement alloc_buffer.
> 
> Without this check, perf may attempt to use a dummy sink that lacks
> alloc_buffer operationsu to initialise perf's ring buffer, leading
> to runtime failures.
> 
> Fixes: 9d3ba0b6c0569 ("Coresight: Add coresight dummy driver")
> Signed-off-by: Yuanfang Zhang <quic_yuanfang@quicinc.com>
> ---
>   drivers/hwtracing/coresight/coresight-core.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index fa758cc21827552a5c97b6bdd05d22dec4994b22..fddf04c5ee46eb4d559416296f7e85ce6c5689fa 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -1374,8 +1374,9 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
>   		goto out_unlock;
>   	}
>   
> -	if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
> -	    csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
> +	if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
> +	     csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
> +	    sink_ops(csdev)->alloc_buffer) {
>   		ret = etm_perf_add_symlink_sink(csdev);
>   
>   		if (ret) {
> 

Looks good to me, I will queue this

Suzuki