Re: [patch 0/9] Fix various __task_cred related invalid RCU assumptions

Peter Zijlstra
2009-12-14T14:31:43Z

On Mon, 2009-12-14 at 06:16 -0800, Paul E. McKenney wrote:

> > I think you can use lock_is_held(&rcu_lock_map), except you need to deal
> > with the !debug_locks case, because lockdep stops once debug_locks
> > becomes false, which means lock_is_held() will return rubbish.
>
> OK, so I need to do something like the following, then?
>
> debug_locks ? lock_is_held(&rcu_lock_map) : 1

Depending on what the safe return value is, yeah. If you want an assert
like function, false is usually the safe one.

#define lockdep_assert_held(l) WARN_ON(debug_locks && !lockdep_is_held(l))

is the one in-tree user of this.