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From: Laura Abbott <labbott@redhat.com>
To: Jianyu Zhan <nasa4836@gmail.com>,
	Laura Abbott <labbott@fedoraproject.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Vlastimil Babka <vbabka@suse.cz>, Michal Hocko <mhocko@suse.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	kernel-hardening@lists.openwall.com,
	Kees Cook <keescook@chromium.org>
Subject: Re: [RFC][PATCH 1/3] mm/debug-pagealloc.c: Split out page poisoning from debug page_alloc
Date: Tue, 26 Jan 2016 12:25:44 -0800	[thread overview]
Message-ID: <56A7D648.8020806@redhat.com> (raw)
In-Reply-To: <CAHz2CGXuUHYHX7KhxGjYtWrKOoxK=2Rz2N-Q0CBR9UWtrYi2Jw@mail.gmail.com>

On 01/25/2016 10:26 PM, Jianyu Zhan wrote:
> On Tue, Jan 26, 2016 at 12:55 AM, Laura Abbott
> <labbott@fedoraproject.org> wrote:
>> +static bool __page_poisoning_enabled __read_mostly;
>> +static bool want_page_poisoning __read_mostly =
>> +       !IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC);
>> +
>
>
> I would say this patch is nice with regard to decoupling
> CONFIG_DEBUG_PAGEALLOC and CONFIG_PAGE_POISONING.
>
> But  since when we enable CONFIG_DEBUG_PAGEALLOC,
> CONFIG_PAGE_POISONING will be selected.
>
> So it would be better to make page_poison.c totally
> CONFIG_DEBUG_PAGEALLOC agnostic,  in case we latter have
> more PAGE_POISONING users(currently only DEBUG_PAGEALLOC ). How about like this:
>
> +static bool want_page_poisoning __read_mostly =
> +       !IS_ENABLED(CONFIG_PAGE_POISONING );
>
> Or just let it default to 'true',  since we only compile this
> page_poison.c when we enable CONFIG_PAGE_POISONING.
>

This patch was just supposed to be the refactor and keep the existing
behavior. There are no Kconfig changes here and the existing behavior
is to poison if !ARCH_SUPPORTS_DEBUG_PAGEALLOC so I think keeping
what I have is appropriate for this particular patch. This can be
updated in another series if appropriate.

Thanks,
Laura
  
>
> Thanks,
> Jianyu Zhan
>

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  reply	other threads:[~2016-01-26 20:25 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-25 16:55 [RFC][PATCH 0/3] Sanitization of buddy pages Laura Abbott
2016-01-25 16:55 ` [RFC][PATCH 1/3] mm/debug-pagealloc.c: Split out page poisoning from debug page_alloc Laura Abbott
2016-01-26  6:26   ` Jianyu Zhan
2016-01-26 20:25     ` Laura Abbott [this message]
2016-01-25 16:55 ` [RFC][PATCH 2/3] mm/page_poison.c: Enable PAGE_POISONING as a separate option Laura Abbott
2016-01-26  6:39   ` Jianyu Zhan
2016-01-26 20:27     ` Laura Abbott
2016-01-25 16:55 ` [RFC][PATCH 3/3] mm/page_poisoning.c: Allow for zero poisoning Laura Abbott
2016-01-25 20:16   ` [kernel-hardening] " Dave Hansen
2016-01-25 22:05     ` Kees Cook
2016-01-26  1:33       ` Laura Abbott
2016-01-26  6:05 ` [RFC][PATCH 0/3] Sanitization of buddy pages Sasha Levin
2016-01-26 20:34   ` Laura Abbott
2016-01-26  9:08 ` [kernel-hardening] " Mathias Krause

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