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From: Christoph Lameter <cl@linux.com>
To: "Liu, XinwuX" <xinwux.liu@intel.com>
Cc: "catalin.marinas@arm.com" <catalin.marinas@arm.com>,
	"penberg@kernel.org" <penberg@kernel.org>,
	"mpm@selenic.com" <mpm@selenic.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"yanmin_zhang@linux.intel.com" <yanmin_zhang@linux.intel.com>,
	"He, Bo" <bo.he@intel.com>, "Chen, Lin Z" <lin.z.chen@intel.com>
Subject: Re: [PATCH] slub/slab: fix kmemleak didn't work on some case
Date: Mon, 8 Jun 2015 04:38:13 -0500 (CDT)	[thread overview]
Message-ID: <alpine.DEB.2.11.1506080425350.10651@east.gentwo.org> (raw)
In-Reply-To: <99C214DF91337140A8D774E25DF6CD5FC89DA2@shsmsx102.ccr.corp.intel.com>

On Mon, 8 Jun 2015, Liu, XinwuX wrote:

> when kernel uses kmalloc to allocate memory, slub/slab will find
> a suitable kmem_cache. Ususally the cache's object size is often
> greater than requested size. There is unused space which contains
> dirty data. These dirty data might have pointers pointing to a block

dirty? In what sense?

> of leaked memory. Kernel wouldn't consider this memory as leaked when
> scanning kmemleak object.

This has never been considered leaked memory before to my knowledge and
the data is already initialized.

F.e. The zeroing function in linux/mm/slub.c::slab_alloc_node() zeros the
complete object and not only the number of bytes specified in the kmalloc
call. Same thing is true for SLAB.

I am a bit confused as to what issue this patch would address.

Also please send clean patches without special characters. Ensure proper
tabbing etc.

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  reply	other threads:[~2015-06-08  9:38 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-08  5:14 Liu, XinwuX
2015-06-08  9:38 ` Christoph Lameter [this message]
2015-06-08 10:13   ` Catalin Marinas
2015-06-09  8:10     ` Zhang, Yanmin
2015-06-09 15:03       ` Catalin Marinas
2015-06-10  7:45         ` Zhang, Yanmin
2015-06-10  9:48           ` Catalin Marinas
2015-06-11  8:18             ` Liu, XinwuX
2015-06-08 10:03 ` Catalin Marinas

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