Re: [PATCH v5 01/10] ring-buffer: Free cpu_buffer::free_page with subbuf_order

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

On Thu, 13 Aug 2026 14:11:43 +0100
Vincent Donnefort <vdonnefort@google.com> wrote:

> When sub-buffers use an order greater than 0, cpu_buffer->free_page is
> allocated with subbuf_order. Use the correct order for
> cpu_buffer->free_page.
> 
> Fixes: f9b94daa542a ("ring-buffer: Set new size of the ring buffer sub page")
> Reported-by: Sashiko <sashiko-bot@kernel.org>
> Signed-off-by: Vincent Donnefort <vdonnefort@google.com>

This looks good to me. (with fixing racing issue.)

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

> 
> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
> index 2667992f0aa2..a3d28b2e2c94 100644
> --- a/kernel/trace/ring_buffer.c
> +++ b/kernel/trace/ring_buffer.c
> @@ -2631,7 +2631,7 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
>  		free_buffer_page(bpage);
>  	}
>  
> -	free_page((unsigned long)cpu_buffer->free_page);
> +	free_pages((unsigned long)cpu_buffer->free_page, cpu_buffer->buffer->subbuf_order);
>  
>  	kfree(cpu_buffer);
>  }
> -- 
> 2.55.0.691.gc56d675ccc-goog
> 
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>