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From: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Andrey Konovalov" <andreyknvl@gmail.com>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"Chinwen Chang (張錦文)" <chinwen.chang@mediatek.com>,
	"Nicholas Tang (鄭秦輝)" <nicholas.tang@mediatek.com>,
	"Yee Lee (李建誼)" <Yee.Lee@mediatek.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-mediatek@lists.infradead.org"
	<linux-mediatek@lists.infradead.org>,
	kasan-dev <kasan-dev@googlegroups.com>,
	james.hsu@mediatek.com, kuan-ying.lee@mediatek.com
Subject: Re: [PATCH] kmemleak: fix kmemleak false positive report with HW tag-based kasan enable
Date: Wed, 24 Nov 2021 10:00:45 +0800	[thread overview]
Message-ID: <3de431c5711c0f6475f54e89c3de601e1279752a.camel@mediatek.com> (raw)
In-Reply-To: <20211119144359.b70d2fde7631bd14cd9652e3@linux-foundation.org>

On Sat, 2021-11-20 at 06:43 +0800, Andrew Morton wrote:
> On Fri, 19 Nov 2021 23:12:55 +0800 Kuan-Ying Lee <
> Kuan-Ying.Lee@mediatek.com> wrote:
> 
> > > > > Call sequence:
> > > > > ptr = kmalloc(size, GFP_KERNEL);
> > > > > page = virt_to_page(ptr);
> > > > > kfree(page_address(page));
> > > > > ptr = kmalloc(size, GFP_KERNEL);
> > > 
> > > How is this call sequence valid? page_address returns the address
> > > of
> > > the start of the page, while kmalloced object could have been
> > > located
> > > in the middle of it.
> > 
> > Thanks for pointing out. I miss the offset.
> > 
> > It should be listed as below.
> > 
> > ptr = kmalloc(size, GFP_KERNEL);
> > page = virt_to_page(ptr);
> > offset = offset_in_page(ptr);
> > kfree(page_address(page) + offset);
> > ptr = kmalloc(size, GFP_KERNEL);
> 
> I updated the changelog to reflect this.

Thanks for updating changelog. :)



  reply	other threads:[~2021-11-24  2:01 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-18  5:44 Kuan-Ying Lee
2021-11-18  9:20 ` Kuan-Ying Lee
2021-11-19 14:15   ` Andrey Konovalov
2021-11-19 15:12     ` Kuan-Ying Lee
2021-11-19 22:43       ` Andrew Morton
2021-11-24  2:00         ` Kuan-Ying Lee [this message]
2021-11-25 16:13   ` Andrey Konovalov
2021-11-28  0:20     ` Andrew Morton
2021-12-02 18:19 ` Catalin Marinas

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