On Fri, Jan 26, 2024 at 06:30:02PM +0100, Thomas Gleixner wrote: > On Wed, Jan 24 2024 at 20:59, Byungchul Park wrote: > > Why is lockdep in the subsystem prefix here? You are changing the CPU > hotplug (not hotplus) code, right? I will fix the typo ;( Thank you. I referred to the commit cb92173d1f047. I will remove the prefix if the way is more desirable. > > cb92173d1f0 ("locking/lockdep, cpu/hotplug: Annotate AP thread") was > > introduced to make lockdep_assert_cpus_held() work in AP thread. > > > > However, the annotation is too strong for that purpose. We don't have to > > use more than try lock annotation for that. > > This lacks a proper explanation why this is too strong. rwsem_acquire() implies: 1. might be a waiter on contention of the lock. 2. enter to the critical section of the lock. All we need in here is to act 2, not 1. That's why I suggested trylock version of annotation for that purpose. Now that dept partially replies on lockdep annotaions for the waiters and events, dept is interpeting rwsem_acquire() as a potential waiter and reports a deadlock by the wait. Of course, the first priority should be not to change the current behavior. I think the change from non-trylock to trylock for the annotation won't. Or am I missing something? Byungchul > > Furthermore, now that Dept was introduced, false positive alarms was > > reported by that. Replaced it with try lock annotation. > > I still have zero idea what this is about. > > Thanks, > > tglx