From: Ingo Molnar <mingo@elte.hu>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <npiggin@suse.de>,
Vegard Nossum <vegard.nossum@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: lockdep and debug objects together are broken?
Date: Wed, 21 Jan 2009 12:54:51 +0100 [thread overview]
Message-ID: <20090121115451.GA20696@elte.hu> (raw)
In-Reply-To: <1232538602.4847.158.camel@laptop>
* Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> On Wed, 2009-01-21 at 12:42 +0100, Ingo Molnar wrote:
>
> > So by the time you'd rearm, there's a lot of tasks with no proper
> > locking state built up. We might be able to re-arm via
> > stop_machine_run perhaps.
>
> Won't work either, kstopmachine only preempts everybody. We'd require
> something stronger.
indeed - mutexes wont be covered.
> What we need is a point where there's guaranteed no locks held, for
> regular tasks that would be a trip to userspace and back, but for kernel
> tasks that's a bit harder -- does the freezer stuff guarantee this?
yes, that might be doable.
Sounds very fragile though.
Ingo
next prev parent reply other threads:[~2009-01-21 11:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-20 8:55 lockdep and debug objects together are broken? Nick Piggin
2009-01-20 21:11 ` Vegard Nossum
2009-01-21 7:19 ` Nick Piggin
2009-01-21 11:42 ` Ingo Molnar
2009-01-21 11:50 ` Peter Zijlstra
2009-01-21 11:54 ` Ingo Molnar [this message]
2009-01-21 11:54 ` Nick Piggin
2009-01-21 11:57 ` Ingo Molnar
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