From: Andi Kleen <andi@firstfloor.org>
To: Anisse Astier <anisse@astier.eu>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
David Rientjes <rientjes@google.com>,
Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
PaX Team <pageexec@freemail.hu>,
Brad Spengler <spender@grsecurity.net>,
Kees Cook <keescook@chromium.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] mm/page_alloc.c: add config option to sanitize freed pages
Date: Sun, 26 Apr 2015 13:12:26 -0700 [thread overview]
Message-ID: <87tww2ejit.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <1429909549-11726-3-git-send-email-anisse@astier.eu> (Anisse Astier's message of "Fri, 24 Apr 2015 23:05:49 +0200")
Anisse Astier <anisse@astier.eu> writes:
> + If unsure, say N.
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 05fcec9..c71440a 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -803,6 +803,11 @@ static bool free_pages_prepare(struct page *page, unsigned int order)
> debug_check_no_obj_freed(page_address(page),
> PAGE_SIZE << order);
> }
> +
> +#ifdef CONFIG_SANITIZE_FREED_PAGES
> + zero_pages(page, order);
> +#endif
And not removing the clear on __GFP_ZERO by remembering that?
That means all clears would be done twice.
That patch is far too simple. Clearing is commonly the most
expensive kernel operation.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
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next prev parent reply other threads:[~2015-04-26 20:12 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-24 21:05 [PATCH 0/2] Sanitizing " Anisse Astier
2015-04-24 21:05 ` [PATCH 1/2] mm/page_alloc.c: cleanup obsolete KM_USER* Anisse Astier
2015-04-24 21:36 ` David Rientjes
2015-04-25 13:43 ` Anisse Astier
2015-04-24 21:05 ` [PATCH 2/2] mm/page_alloc.c: add config option to sanitize freed pages Anisse Astier
2015-04-24 21:38 ` David Rientjes
2015-04-25 13:52 ` Anisse Astier
2015-04-26 20:12 ` Andi Kleen [this message]
2015-04-27 8:11 ` Anisse Astier
2015-04-27 9:25 ` PaX Team
2015-04-27 21:27 ` Anisse Astier
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