Re: [PATCH] workaround minor lockdep bug triggered by mm_take_all_locks

David Miller
2008-08-04T21:57:48Z

From: Andrea Arcangeli <andrea@qumranet.com>
Date: Mon, 4 Aug 2008 23:09:54 +0200

> On Mon, Aug 04, 2008 at 10:37:22PM +0200, Peter Zijlstra wrote:
> > You're so wrong it not even funny. It reports about deadlocks before
> > they happen. All it needs is to observe a lock order violation and it
>
> Now tell me how it helps to report them... It tells me the system has
> crashed and where, it's not like I couldn't figure it out by myself
> but just noticing nothing works and all cpus are spinning in some
> spinlock slow path and pressing sysrq+t/p.

It tells you about deadlock scenerios that you haven't even encoutered
yet. It shows bugs for parallel code path sequences that have not
even occurred yet.

But I think you're beyond the point of being able to see why lockdep
is valuable. So why don't we just move on.