Re: [PATCH] trace/osnoise: Do not use 'main' as variable name

[Randy Dunlap]

On 9/8/21 8:53 AM, Steven Rostedt wrote:
> On Wed,  8 Sep 2021 08:14:07 -0700
> Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
>
> > gcc 11.x may get a hiccup when encountering 'main' as variable name.
> >
> > kernel/trace/trace_osnoise.c: In function 'start_kthread':
> > kernel/trace/trace_osnoise.c:1515:8: error: 'main' is usually a function
> >
> > Use a different variable name to silence it.
>
> Egad, no. NACK! Double NACK. Linus already NACK'd this.
>
> (although it's ironic that he also added -Werror as the default :-/ )
>
> The bug in is in gcc, go send them a patch.
>
> THERE IS NO ISSUE WITH HAVING A LOCAL VARIABLE NAMED "main"!!!!
>
> This has already been discussed:
>
>    https://lore.kernel.org/all/CAHk-=whHxeUjaNrWOLb0qx=-nibRZzQomwkw9xMPH_aHCf=BWQ@xxxxxxxxxxxxxx/
>
> For now, the workaround is this patch:
>
>     https://lore.kernel.org/all/20210813224131.25803-1-rdunlap@xxxxxxxxxxxxx/
>
>
> -- Steve
>
>
> > Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > ---
> >   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 65b08b8e5bf8..7a4c73b4fdcf 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 *func = osnoise_main;
> >   	char comm[24];
> >   
> >   #ifdef CONFIG_TIMERLAT_TRACER
> >   	if (osnoise_data.timerlat_tracer) {
> >   		snprintf(comm, 24, "timerlat/%d", cpu);
> > -		main = timerlat_main;
> > +		func = 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(func, NULL, cpu, comm);
> >   
> >   	if (IS_ERR(kthread)) {
> >   		pr_err(BANNER "could not start sampling thread\n");

Preferably Linus's version:

https://lore.kernel.org/all/73ee98a4-c4a5-04f3-6280-dcd67507d889@xxxxxxxxxxxxx/


--
~Randy