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From: Andrew Morton <akpm@linux-foundation.org>
To: Alexander Potapenko <glider@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>,
	Andrey Konovalov <andreyknvl@google.com>,
	Jann Horn <jannh@google.com>, LKML <linux-kernel@vger.kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>,
	kasan-dev <kasan-dev@googlegroups.com>,
	Marco Elver <elver@google.com>
Subject: Re: [PATCH mm] kfence, slab: fix cache_alloc_debugcheck_after() for bulk allocations
Date: Thu, 4 Mar 2021 17:31:32 -0800	[thread overview]
Message-ID: <20210304173132.6696eb2a357edf835a5033ee@linux-foundation.org> (raw)
In-Reply-To: <CAG_fn=XVAFjgkFCj8kc6Bz4rvBwCeE4HUcJPBTWQcNjrBLaT=g@mail.gmail.com>

On Thu, 4 Mar 2021 22:05:48 +0100 Alexander Potapenko <glider@google.com> wrote:

> On Thu, Mar 4, 2021 at 9:53 PM Marco Elver <elver@google.com> wrote:
> >
> > cache_alloc_debugcheck_after() performs checks on an object, including
> > adjusting the returned pointer. None of this should apply to KFENCE
> > objects. While for non-bulk allocations, the checks are skipped when we
> > allocate via KFENCE, for bulk allocations cache_alloc_debugcheck_after()
> > is called via cache_alloc_debugcheck_after_bulk().
> 
> @Andrew, is this code used by anyone?
> As far as I understand, it cannot be enabled by any config option, so
> nobody really tests it.
> If it is still needed, shall we promote #if DEBUGs in slab.c to a
> separate config option, or maybe this code can be safely removed?

It's all used:

#ifdef CONFIG_DEBUG_SLAB
#define	DEBUG		1
#define	STATS		1
#define	FORCED_DEBUG	1
#else
#define	DEBUG		0
#define	STATS		0
#define	FORCED_DEBUG	0
#endif



  reply	other threads:[~2021-03-05  1:31 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-04 20:52 Marco Elver
2021-03-04 21:05 ` Alexander Potapenko
2021-03-05  1:31   ` Andrew Morton [this message]
2021-03-05  8:57     ` Alexander Potapenko

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