Re: [PATCH] coresight: fix missing error code when trace ID is invalid

[James Clark]

On 08/05/2026 6:45 am, Jie Gan wrote:
> When coresight_path_assign_trace_id() fails to allocate a valid trace
> ID, the code jumps to err_path without setting ret to an error value.
> This causes coresight_enable_sysfs() to return 0 (success) to the
> caller even though no trace session was started.
>
> Set ret = -EINVAL before the goto so that callers receive a proper
> error code.
>
> Fixes: d87d76d823d1 ("Coresight: Allocate trace ID after building the path")
> Signed-off-by: Jie Gan <jie.gan@xxxxxxxxxxxxxxxx>
> ---
>   drivers/hwtracing/coresight/coresight-sysfs.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
> index d2a6ed8bcc74..c9338c783540 100644
> --- a/drivers/hwtracing/coresight/coresight-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-sysfs.c
> @@ -195,42 +195,44 @@ int coresight_enable_sysfs(struct coresight_device *csdev)
>   		 */
>   		if (subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE)
>   			csdev->refcnt++;
>   		goto out;
>   	}
>   
>   	sink = coresight_find_activated_sysfs_sink(csdev);
>   	if (!sink) {
>   		ret = -EINVAL;
>   		goto out;
>   	}
>   
>   	path = coresight_build_path(csdev, sink);
>   	if (IS_ERR(path)) {
>   		pr_err("building path(s) failed\n");
>   		ret = PTR_ERR(path);
>   		goto out;
>   	}
>   
>   	coresight_path_assign_trace_id(path, CS_MODE_SYSFS);
> -	if (!IS_VALID_CS_TRACE_ID(path->trace_id))
> +	if (!IS_VALID_CS_TRACE_ID(path->trace_id)) {
> +		ret = -EINVAL;
>   		goto err_path;
> +	}
>   
>   	ret = coresight_enable_path(path, CS_MODE_SYSFS);
>   	if (ret)
>   		goto err_path;
>   
>   	ret = coresight_enable_source_sysfs(csdev, CS_MODE_SYSFS, path);
>   	if (ret)
>   		goto err_source;
>   
>   	switch (subtype) {
>   	case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
>   		/*
>   		 * When working from sysFS it is important to keep track
>   		 * of the paths that were created so that they can be
>   		 * undone in 'coresight_disable()'.  Since there can only
>   		 * be a single session per tracer (when working from sysFS)
>   		 * a per-cpu variable will do just fine.
>   		 */
>   		cpu = source_ops(csdev)->cpu_id(csdev);
>   		per_cpu(tracer_path, cpu) = path;
>
> ---
> base-commit: 17c7841d09ee7d33557fd075562d9289b6018c90
> change-id: 20260508-fix-trace-id-error-dbfdd4d8f2d1
>
> Best regards,

Reviewed-by: James Clark <james.clark@xxxxxxxxxx>