Re: [RFC PATCH v4 5/7] sched, tracing: add to report task state in symbolic chars

[Steven Rostedt <rostedt@xxxxxxxxxxx>]

On Thu, 3 Aug 2023 10:38:43 +0800
Ze Gao <zegao2021@xxxxxxxxx> wrote:

> > > +static inline char __trace_sched_switch_state_char(bool preempt,
> > > +                                                unsigned int prev_state,
> > > +                                                struct task_struct *p)
> > > +{
> > > +     long state;
> > > +
> > > +#ifdef CONFIG_SCHED_DEBUG
> > > +     BUG_ON(p != current);  
> >
> > BUG? Why not WARN_ON()?  
> 
> I directly copied it from __trace_sched_switch_state since they
> are very similar. I had doubt on this too but decided to keep it in
> case people want to be 100% sure that the current task is exactly
> the one that is being switched, otherwise it's a fatal problem for
> scheduler at the point where trace_sched_switch is called.
> 
> If you think WARN_ON_ONCE is more appropriate, I can fix both
> in v6.
> 
> Thoughts?

Yeah, that BUG_ON is from 2014, and really should not BUG.

I'd fix both.

Thanks!

-- Steve