[PATCH v18 3/8] ring-buffer: Skip invalid sub-buffers when validating persistent ring buffer

[Steven Rostedt]

On Thu, 30 Apr 2026 00:15:59 +0900
Masami Hiramatsu (Google) <mhiramat at kernel.org> wrote:

> It should not be a never ending loop (there are other exit conditions),
> but I agreed. What about limiting with nr_subbufs?
> 
> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
> index 5326924615a4..aa89ec96e964 100644
> --- a/kernel/trace/ring_buffer.c
> +++ b/kernel/trace/ring_buffer.c
> @@ -5630,7 +5630,8 @@ __rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
>  	 * a case where we will loop three times. There should be no
>  	 * reason to loop four times (that I know of).
>  	 */
> -	if (RB_WARN_ON(cpu_buffer, ++nr_loops > 3)) {
> +	if (RB_WARN_ON(cpu_buffer,
> +		++nr_loops > (cpu_buffer->ring_meta ? cpu_buffer->nr_subbufs : 3))) {
>  		reader = NULL;
>  		goto out;
>  	}

Yeah, this looks more reasonable.

Thanks,

-- Steve