Re: [PATCH v14 2/5] ring-buffer: Skip invalid sub-buffers when validating persistent ring buffer

[Steven Rostedt]

On Mon, 30 Mar 2026 16:22:10 -0400
Steven Rostedt <rost...@goodmis.org> wrote:

> On Mon, 30 Mar 2026 21:50:04 +0900
> "Masami Hiramatsu (Google)" <mhira...@kernel.org> wrote:
> 
> > @@ -2042,7 +2065,8 @@ static void rb_meta_validate_events(struct 
> > ring_buffer_per_cpu *cpu_buffer)
> >     local_set(&cpu_buffer->entries, entries);
> >     local_set(&cpu_buffer->entries_bytes, entry_bytes);
> >  
> > -   pr_info("Ring buffer meta [%d] is from previous boot!\n", 
> > cpu_buffer->cpu);
> > +   pr_info("Ring buffer meta [%d] is from previous boot! (%d pages 
> > discarded)\n",
> > +           cpu_buffer->cpu, discarded);  
> 
> As pages should never be discarded unless something went wrong, let's only
> print that if there were discarded pages.
> 
>       if (discarded) {
>               pr_info("Ring buffer meta [%d] is from previous boot! (%d pages 
> discarded)\n",
>                       cpu_buffer->cpu, discarded);
>       } else {
>               pr_info("Ring buffer meta [%d] is from previous boot!\n", 
> cpu_buffer->cpu);
>       }

Or perhaps:

        pr_info("Ring buffer meta [%d] is from previous boot!", 
cpu_buffer->cpu);
        if (discarded)
                pr_cont(" (%d pages discarded)", discarded);
        pr_cont("\n");

-- Steve