Re: [PATCH v2 05/10] tracing/boot: Show correct histogram error command

[Masami Hiramatsu]

On Tue, 10 Aug 2021 00:48:26 +0900
Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:

> Since trigger_process_regex() modifies given trigger actions
> while parsing, the error message couldn't show what command
> was passed to the trigger_process_regex() when it returns
> an error.
> 
> To fix that, show the backed up trigger action command
> instead of parsed buffer.
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> ---
>  kernel/trace/trace_boot.c |   11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
> index 69558f149620..cfe4a415b468 100644
> --- a/kernel/trace/trace_boot.c
> +++ b/kernel/trace/trace_boot.c
> @@ -422,6 +422,7 @@ trace_boot_init_histograms(struct trace_event_file *file,
>  {
>  	struct xbc_node *node;
>  	const char *p;
> +	char *tmp;
>  
>  	xbc_node_for_each_subkey(hnode, node) {
>  		p = xbc_node_get_data(node);
> @@ -429,15 +430,19 @@ trace_boot_init_histograms(struct trace_event_file *file,
>  			continue;
>  		/* All digit started node should be instances. */
>  		if (trace_boot_compose_hist_cmd(node, buf, size) == 0) {
> +			tmp = kstrdup(buf, GFP_KERNEL);
>  			if (trigger_process_regex(file, buf) < 0)
> -				pr_err("Failed to apply hist trigger: %s\n", buf);
> +				pr_err("Failed to apply hist trigger: %s\n", tmp);
> +			kfree(tmp);
>  		}
>  	}
>  
>  	if (xbc_node_find_child(hnode, "keys")) {
>  		if (trace_boot_compose_hist_cmd(hnode, buf, size) == 0)
> +			tmp = kstrdup(buf, GFP_KERNEL);
>  			if (trigger_process_regex(file, buf) < 0)
> -				pr_err("Failed to apply hist trigger: %s\n", buf);
> +				pr_err("Failed to apply hist trigger: %s\n", tmp);
> +			kfree(tmp);

And this lacks '{}' for the 2nd if...

>  	}
>  }
>  #else
> @@ -488,7 +493,7 @@ trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
>  			if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
>  				pr_err("action string is too long: %s\n", p);
>  			else if (trigger_process_regex(file, buf) < 0)
> -				pr_err("Failed to apply an action: %s\n", buf);
> +				pr_err("Failed to apply an action: %s\n", p);
>  		}
>  		anode = xbc_node_find_child(enode, "hist");
>  		if (anode)
> 


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>