linux-kernel - Re: [PATCH 01/15] kmemleak: Add the base support

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Date:	Fri, 12 Dec 2008 15:14:59 +0200
From:	Pekka Enberg <penberg@...helsinki.fi>
To:	Catalin Marinas <catalin.marinas@....com>
Cc:	linux-kernel@...r.kernel.org,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 01/15] kmemleak: Add the base support

On Fri, 2008-12-12 at 11:36 +0000, Catalin Marinas wrote:
> On Fri, 2008-12-12 at 00:01 +0200, Pekka Enberg wrote:
> > On Wed, Dec 10, 2008 at 8:26 PM, Catalin Marinas
> > <catalin.marinas@....com> wrote:
> > > +static void put_object(struct memleak_object *object)
> > > +{
> > > +       if (!atomic_dec_and_test(&object->use_count))
> > > +               return;
> > > +
> > > +       /* should only get here after delete_object was called */
> > > +       BUG_ON(object->flags & OBJECT_ALLOCATED);
> > 
> > This could be
> > 
> >     if (WARN_ON(object->flags & OBJECT_ALLOCATED))
> >             return;
> 
> I'm not sure just warning would be enough. If this happens, its a severe
> bug in kmemleak and the tool is no longer useful (it could even leak
> memory or free already freed blocks). I could change it to a
> memleak_panic call but if the object use_count isn't reliable, the
> memleak_disable call wouldn't work properly either.

Oh, we use WARN_ON() for things like this as well to maximize the
likelihood of the oops actually reaching the user. But whatever works
for you the best.

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