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Date: Thu, 4 Sep 2014 07:14:11 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Peter Hurley <peter@hurleysoftware.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jslaby@suse.cz>,
        One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
        linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 13/26] locking: Add non-fatal spin lock assert
Message-ID: <20140904051411.GA27350@gmail.com>
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* Peter Zijlstra <peterz@infradead.org> wrote:

> On Wed, Sep 03, 2014 at 10:50:01AM -0400, Peter Hurley wrote:
> > So a lockdep-only assert is unlikely to draw attention to existing bugs,
> > especially in established drivers.
> 
> By the same logic lockdep will not find locking errors in established
> drivers.

Indeed, this patch is ill-advised in several ways:

  - it extends an API variant that we want to phase

  - emits a warning even if say lockdep has already emitted a
    warning and locking state is not guaranteed to be consistent. 

  - makes the kernel more expensive once fully debugged, in that
    non-fatal checks are unconditional.

Also please submit locking related patches as standalone series 
to the locking subsystem, not embedded in an unrelated series.

Thanks,

	Ingo