Re: [RT WARNING] DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current) with fsfreeze (4.19.25-rt16)

From: Oleg Nesterov
Date: Tue Apr 30 2019 - 10:15:17 EST


Sorry, I don't understand...

On 04/30, Peter Zijlstra wrote:
>
> Thaw then does the reverse, frobs lockdep

Yes, in particular it does

lockdep_sb_freeze_acquire()
percpu_rwsem_acquire()
sem->rw_sem.owner = current;


> and then does: percpu_up_write().
>
> percpu_up_write() on up_write(). And note how __up_write() has:
>
> DEBUG_RWSEMS_WARN_ON(sem->owner != current, sem);

and everything looks correct, sem->owner == current by the time
thaw_super_locked() does percpu_up_write/up_write.

Oleg.