Re: [PATCH] trace: Fix some checker warnings

[David Howells <dhowells@redhat.com>]

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

> Could you remove that part from your printf checker macro, and
> apply the below patch?
> Since the printf macros are a kind of improvement but this part is an
> actual bug, need to be fixed on stable kernel too.

Sure.  Posted that as v2.

> From 2e993ec80d864677fd42d27f9d4ee01d7e63f8a4 Mon Sep 17 00:00:00 2001
> From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
> Date: Mon, 5 Dec 2022 14:27:00 +0900
> Subject: [PATCH] tracing: Fix complicated dependency of
>  CONFIG_TRACER_MAX_TRACE
> 
> Both CONFIG_OSNOISE_TRACER and CONFIG_HWLAT_TRACER partially enables the
> CONFIG_TRACER_MAX_TRACE code, but that is complicated and has
> introduced a bug; It declares tracing_max_lat_fops data structure outside
> of #ifdefs, but since it is defined only when CONFIG_TRACER_MAX_TRACE=y
> or CONFIG_HWLAT_TRACER=y, if only CONFIG_OSNOISE_TRACER=y, that
> declaration comes to a definition(!).
> 
> To fix this issue, and do not repeat the similar problem, makes
> CONFIG_OSNOISE_TRACER and CONFIG_HWLAT_TRACER enables the
> CONFIG_TRACER_MAX_TRACE always. It has there benefits;
> - Fix the tracing_max_lat_fops bug
> - Simplify the #ifdefs
> - CONFIG_TRACER_MAX_TRACE code is fully enabled, or not.
> 
> Fixes: 424b650f35c7 ("tracing: Fix missing osnoise tracer on max_latency")
> Cc: stable@vger.kernel.org
> Reported-by: David Howells <dhowells@redhat.com>
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Tested-by: David Howells <dhowells@redhat.com>