Re: [PATCH v4 1/2] tracing: Return ERR_PTR() from expr_str()

[Steven Rostedt <rostedt@goodmis.org>]

On Thu, 21 May 2026 10:28:16 +0800
Pengpeng Hou <pengpeng@iscas.ac.cn> wrote:

> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 0dbbf6cca9bc..0b33bb8ef6f7 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -1769,18 +1769,18 @@ static void expr_field_str(struct hist_field *field, char *expr)
>  
>  static char *expr_str(struct hist_field *field, unsigned int level)
>  {
> -	char *expr;
> +	char *expr __free(kfree) = NULL;

Can you split this into two patches.

1. Change expr to use __free(kfree)

2. Update to use ERR_PTR()

as they are two distinct changes.

Thanks,

-- Steve

>  
>  	if (level > 1)
> -		return NULL;
> +		return ERR_PTR(-EINVAL);
>  
>  	expr = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
>  	if (!expr)
> -		return NULL;
> +		return ERR_PTR(-ENOMEM);
>  
>  	if (!field->operands[0]) {
>  		expr_field_str(field, expr);
> -		return expr;
> +		return_ptr(expr);
>  	}