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Message-ID: <19f34abd0801271330j596cd9fbqbd3691548dff26@mail.gmail.com>
Date: Sun, 27 Jan 2008 22:30:10 +0100
From: "Vegard Nossum" <vegard.nossum@gmail.com>
To: "Pekka J Enberg" <penberg@cs.helsinki.fi>
Subject: Re: lib/idr.c: initialize struct idr_layer
Cc: "Jim Houston" <jim.houston@ccur.com>, "Ingo Molnar" <mingo@elte.hu>,
       "Tejun Heo" <htejun@gmail.com>,
       "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
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On Jan 27, 2008 10:21 PM, Pekka J Enberg <penberg@cs.helsinki.fi> wrote:
> On Sun, 27 Jan 2008, Vegard Nossum wrote:
> > Though in this case, idr_pre_get() actually *is* called first. Hmm...
> > I think there's a pretty big chance that kmemcheck is at fault :-(
>
> Depends on how you track object initialization. An object returned by
> kmem_cache_alloc() is always initialized if the cache it comes from has a
> constructor.

I think there's a pretty big chance I'm wrong (or misunderstanding
something) here, so I'll just ask:
setup_object() from mm/slub.c is what calls the ctor. Shouldn't this
be called from slab_alloc() as well? (I'm marking the data
"uninitialized" there before returning the object.) Otherwise you
might get back an object that is initialized with the previous owner's
data. Or is this intentional?

Thanks.

Vegard