Re: [PATCH 2/5] kprobes: Use guard() for external locks

[Peter Zijlstra]

On Mon, Dec 09, 2024 at 11:41:26AM +0900, Masami Hiramatsu (Google) wrote:
> From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> 
> Use guard() for text_mutex, cpu_read_lock, and jump_label_lock in
> the kprobes.

> @@ -853,29 +850,24 @@ static void try_to_optimize_kprobe(struct kprobe *p)
>  		return;
>  
>  	/* For preparing optimization, jump_label_text_reserved() is called. */
> -	cpus_read_lock();
> -	jump_label_lock();
> -	mutex_lock(&text_mutex);
> +	guard(cpus_read_lock)();
> +	guard(jump_label_lock)();
> +	guard(mutex)(&text_mutex);
>  

> @@ -1294,62 +1280,55 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
>  	int ret = 0;
>  	struct kprobe *ap = orig_p;
>  
> -	cpus_read_lock();
> -
> -	/* For preparing optimization, jump_label_text_reserved() is called */
> -	jump_label_lock();
> -	mutex_lock(&text_mutex);

Why does kprobe need jump_label_lock and how does it then not also need
static_call_lock ?