Re: [PATCH rcu 1/9] rcu: Add lockdep_assert_in_rcu_read_lock() and friends

Jeff Johnson
2025-02-20T19:38:20Z

On 6/4/24 15:23, Paul E. McKenney wrote:
> There is no direct RCU counterpart to lockdep_assert_irqs_disabled()
> and friends. Although it is possible to construct them, it would
> be more convenient to have the following lockdep assertions:
>
> lockdep_assert_in_rcu_read_lock()
> lockdep_assert_in_rcu_read_lock_bh()
> lockdep_assert_in_rcu_read_lock_sched()
> lockdep_assert_in_rcu_reader()
>
> This commit therefore creates them.

I'm looking at some downstream code that is trying to become
upstream compliant, and currently that code uses:

RCU_LOCKDEP_WARN(!rcu_read_lock_held(), "some message");

It seems like this would be a good use of one of these helper
functions, but I'm shocked to see that no upstream code is using
them yet.

Is there a reason to not use these helpers?

/jeff