Re: [Question] Detecting Sleep-in-Atomic Context in PREEMPT_RT via RV (Runtime Verification) monitor rtapp:sleep

[Nam Cao <namcao@linutronix.de>]

Yunseong Kim <ysk@kzalloc.com> writes:
> I specifically believe that RV can encompass the role of
> CONFIG_DEBUG_ATOMIC_SLEEP and even go beyond it.
>
> My reasoning is that even if a sleepable (PREEMPT_RT) spinlock is used 
> within an IRQ/preemption disabled section, CONFIG_DEBUG_ATOMIC_SLEEP 
> might not trigger a warning if scheduling does not actually occur (i.e., 
> if there is no contention for that spinlock). This is because the actual 
> debugging check happens in __might_resched().

That's not how it works. See the description of CONFIG_DEBUG_ATOMIC_SLEEP:

"If you say Y here, various routines which may sleep will become very
noisy if they are called inside atomic sections: when a spinlock is
held, inside an rcu read side critical section, inside preempt disabled
sections, inside an interrupt, etc..."

Nam