Re: [RFC PATCH 1/7] tracing/probe: Check maxactive error cases

[Steven Rostedt]

On Wed, 13 Mar 2019 21:27:42 +0900
Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:

> Check maxactive on kprobe error case, because maxactive
> is only for kretprobe, not for kprobe. Also, maxactive
> should not be 0, it should be at least 1.
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> ---
>  kernel/trace/trace_kprobe.c |   10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index d5fb09ebba8b..d47e12596f12 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -624,7 +624,11 @@ static int trace_kprobe_create(int argc, const char *argv[])
>  	if (event)
>  		event++;
>  
> -	if (is_return && isdigit(argv[0][1])) {
> +	if (isdigit(argv[0][1])) {
> +		if (!is_return) {
> +			pr_info("Maxactive is not for kprobe");

So now 'p1:..." will error out and not just be ignored?

-- Steve

> +			return -EINVAL;
> +		}
>  		if (event)
>  			len = event - &argv[0][1] - 1;
>  		else
> @@ -634,8 +638,8 @@ static int trace_kprobe_create(int argc, const char *argv[])
>  		memcpy(buf, &argv[0][1], len);
>  		buf[len] = '\0';
>  		ret = kstrtouint(buf, 0, &maxactive);
> -		if (ret) {
> -			pr_info("Failed to parse maxactive.\n");
> +		if (ret || !maxactive) {
> +			pr_info("Invalid maxactive number\n");
>  			return ret;
>  		}
>  		/* kretprobes instances are iterated over via a list. The