Re: [PATCH v2] tracing: Fix selftest config check for function graph start up test

[Jiri Olsa <jolsa@redhat.com>]

On Thu, Oct 21, 2021 at 01:43:57PM -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> There's a new test in trace_selftest_startup_function_graph() that
> requires the use of ftrace args being supported as well does some tricks
> with dynamic tracing. Although this code checks HAVE_DYNAMIC_FTRACE_WITH_ARGS
> it fails to check DYNAMIC_FTRACE, and the kernel fails to build due to
> that dependency.
> 
> Also only define the prototype of trace_direct_tramp() if it is used.
> 
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Acked-by: Jiri Olsa <jolsa@redhat.com>

thanks,
jirka

> ---
> Changes since v1:
>    https://lkml.kernel.org/r/20211021123729.23be20c4@gandalf.local.home
>    - Hide trace_direct_tramp() when not used
> 
>  kernel/trace/trace_selftest.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
> index 3404a245417e..afd937a46496 100644
> --- a/kernel/trace/trace_selftest.c
> +++ b/kernel/trace/trace_selftest.c
> @@ -784,7 +784,11 @@ static struct fgraph_ops fgraph_ops __initdata  = {
>  	.retfunc		= &trace_graph_return,
>  };
>  
> +#if defined(CONFIG_DYNAMIC_FTRACE) && \
> +    defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS)
> +#define TEST_DIRECT_TRAMP
>  noinline __noclone static void trace_direct_tramp(void) { }
> +#endif
>  
>  /*
>   * Pretty much the same than for the function tracer from which the selftest
> @@ -845,7 +849,7 @@ trace_selftest_startup_function_graph(struct tracer *trace,
>  		goto out;
>  	}
>  
> -#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
> +#ifdef TEST_DIRECT_TRAMP
>  	tracing_reset_online_cpus(&tr->array_buffer);
>  	set_graph_array(tr);
>  
> -- 
> 2.31.1
>