On Thu, May 24, 2018 at 03:38:51PM +0800, Jason Yan wrote:
>
>
> On 2018/5/24 15:15, Sebastian Andrzej Siewior wrote:
> > On 2018-05-24 10:58:44 [+0800], Jason Yan wrote:
> > > I think it's fine to delete this irq save code. As for the "TODO"
> > > comment, I think we can add:
> > >
> > > BUG_ON(!irqs_disabled());
> > >
> > > or
> > >
> > > WARN_ON_ONCE(!irqs_disabled());
> >
> > no, please don't do this. Please add instead
> > lockdep_assert_held()
> >
> > on the lock in question and let lockdep to its work. Lockdep has way
> > better coverage than your irqs_disabled() check which also breaks RT.
> >
>
> lockdep_assert_held() cannot detect the irq state, it can only detect
> whether we have held the lock.
I think Sebastian wanted to say lockdep_assert_irqs_disabled().
Either way, please never ever use BUG_ON() (even WARN_ON() is
questionable as some people actually use panic_on_oops). It causes
nasty bugs at customer sites.
Byte,
Johannes
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