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Message-ID: <1565598290.5872.6.camel@mtkswgap22>
Subject: Re: [RFC PATCH v2] mm: slub: print kernel addresses in slub debug
 messages
From:   Miles Chen <miles.chen@mediatek.com>
To:     Matthew Wilcox <willy@infradead.org>
CC:     Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
        <linux-mediatek@lists.infradead.org>, <wsd_upstream@mediatek.com>,
        "Tobin C . Harding" <me@tobin.cc>,
        Kees Cook <keescook@chromium.org>
Date:   Mon, 12 Aug 2019 16:24:50 +0800
In-Reply-To: <20190809142617.GO5482@bombadil.infradead.org>
References: <20190809010837.24166-1-miles.chen@mediatek.com>
         <20190809024644.GL5482@bombadil.infradead.org>
         <1565359918.12824.20.camel@mtkswgap22>
         <20190809142617.GO5482@bombadil.infradead.org>
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On Fri, 2019-08-09 at 07:26 -0700, Matthew Wilcox wrote:
> On Fri, Aug 09, 2019 at 10:11:58PM +0800, Miles Chen wrote:
> > On Thu, 2019-08-08 at 19:46 -0700, Matthew Wilcox wrote:
> > > On Fri, Aug 09, 2019 at 09:08:37AM +0800, miles.chen@mediatek.com wrote:
> > > > INFO: Slab 0x(____ptrval____) objects=25 used=10 fp=0x(____ptrval____)
> > > 
> > > ... you don't have any randomness on your platform?
> > 
> > We have randomized base on our platforms.
> 
> Look at initialize_ptr_random().  If you have randomness, then you
> get a siphash_1u32() of the address.  With no randomness, you get this
> ___ptrval___ string instead.
> 
You are right. There is no randomness in this platform. (I ran my test
code on Qemu with no randomness)


thanks again