Re: [PATCH v3 1/3] lockdep: Make LOCKDEP_CROSSRELEASE configs all part of PROVE_LOCKING
From: Byungchul Park
Date: Thu Aug 24 2017 - 02:12:02 EST
On Wed, Aug 23, 2017 at 07:47:14PM +0200, Peter Zijlstra wrote:
> Those are fine and are indeed the flush_work() vs work inversion.
>
> The two straight forward annotations are:
>
> flush_work(work) process_one_work(wq, work)
> A(work) A(work)
> R(work) work->func(work);
> R(work)
>
> Which catches:
>
> Task-1: work:
>
> mutex_lock(&A); mutex_lock(&A);
> flush_work(work);
I'm not sure but, with LOCKDEP_COMPLETE enabled, this issue would
automatically be covered w/o additional A(work)/R(work). Right?
A(work)/R(work) seem to be used for preventing wait_for_completion()
in flush_work() from waiting for the completion forever because of the
work using mutex_lock(&A). Am I understanding correctly?
If yes, we can use just LOCKDEP_COMPLETE for that purpose.
> And the analogous:
>
> flush_workqueue(wq) process_one_work(wq, work)
> A(wq) A(wq)
> R(wq) work->func(work);
> (wq)