Re: [PATCH] trace_osnoise: rename main to trace_main to avoid Werror=main

[Steven Rostedt]

On Mon,  6 Sep 2021 17:40:03 +0800
Jackie Liu <liu.yun@xxxxxxxxx> wrote:

> From: Jackie Liu <liuyun01@xxxxxxxxxx>
> 
> kernel builds with -Werror=main, gcc report failed.
> 
> Avoids warnings like:
> kernel/trace/trace_osnoise.c:1515:8: error: ‘main’ is usually a function [-Werror=main]

NACK!

It's a stupid warning, and likely a bug in the compiler.

There's nothing wrong with using "main" as a local variable. It will
*never* conflict with the main main. Less so in the kernel, as the
kernel doesn't even have a main!

Do not send patches to fix this "error".

Not to mention, we already went through this discussion a month ago.

  https://lore.kernel.org/all/20210813224131.25803-1-rdunlap@xxxxxxxxxxxxx/

-- Steve

> 
> Fixes: a955d7eac177 ("trace: Add timerlat tracer")
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Signed-off-by: Jackie Liu <liuyun01@xxxxxxxxxx>
> ---
>  kernel/trace/trace_osnoise.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
> index b61eefe5ccf5..938e2791010a 100644
> --- a/kernel/trace/trace_osnoise.c
> +++ b/kernel/trace/trace_osnoise.c
> @@ -1512,20 +1512,20 @@ static void stop_per_cpu_kthreads(void)
>  static int start_kthread(unsigned int cpu)
>  {
>  	struct task_struct *kthread;
> -	void *main = osnoise_main;
> +	void *trace_main = osnoise_main;
>  	char comm[24];
>  
>  #ifdef CONFIG_TIMERLAT_TRACER
>  	if (osnoise_data.timerlat_tracer) {
>  		snprintf(comm, 24, "timerlat/%d", cpu);
> -		main = timerlat_main;
> +		trace_main = timerlat_main;
>  	} else {
>  		snprintf(comm, 24, "osnoise/%d", cpu);
>  	}
>  #else
>  	snprintf(comm, 24, "osnoise/%d", cpu);
>  #endif
> -	kthread = kthread_create_on_cpu(main, NULL, cpu, comm);
> +	kthread = kthread_create_on_cpu(trace_main, NULL, cpu, comm);
>  
>  	if (IS_ERR(kthread)) {
>  		pr_err(BANNER "could not start sampling thread\n");