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From: Michal Hocko <mhocko@kernel.org>
To: Dianzhang Chen <dianzhangchen0@gmail.com>
Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com,
	iamjoonsoo.kim@lge.com, akpm@linux-foundation.org,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/slab_common.c: fix possible spectre-v1 in kmalloc_slab()
Date: Wed, 29 May 2019 19:49:31 +0200	[thread overview]
Message-ID: <20190529174931.GH18589@dhcp22.suse.cz> (raw)
In-Reply-To: <CAFbcbMDJB0uNjTa9xwT9npmTdqMJ1Hez3CyeOCjjrLF2W0Wprw@mail.gmail.com>

On Thu 30-05-19 00:39:53, Dianzhang Chen wrote:
> It's come from `192+1`.
> 
> 
> The more code fragment is:
> 
> 
> if (size <= 192) {
> 
>     if (!size)
> 
>         return ZERO_SIZE_PTR;
> 
>     size = array_index_nospec(size, 193);
> 
>     index = size_index[size_index_elem(size)];
> 
> }

OK I see, I could have looked into the code, my bad. But I am still not
sure what is the potential exploit scenario and why this particular path
a needs special treatment while other size branches are ok. Could you be
more specific please?
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2019-05-29 17:49 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-29 12:37 Dianzhang Chen
2019-05-29 16:25 ` Michal Hocko
2019-05-29 16:39   ` Dianzhang Chen
2019-05-29 17:49     ` Michal Hocko [this message]
2019-05-30  5:20       ` Dianzhang Chen
2019-05-30  6:24         ` Michal Hocko
2019-05-30  7:01           ` Dianzhang Chen
2019-05-29 19:48 ` Matthew Wilcox
2019-05-30  5:21   ` Dianzhang Chen
2019-05-29 20:31 Alexey Dobriyan
2019-05-30  0:04 ` Matthew Wilcox

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