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
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
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
next prev parent reply other threads:[~2015-04-26 20:12 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-24 21:05 [PATCH 0/2] Sanitizing freed pages Anisse Astier
2015-04-24 21:05 ` Anisse Astier
2015-04-24 21:05 ` [PATCH 1/2] mm/page_alloc.c: cleanup obsolete KM_USER* Anisse Astier
2015-04-24 21:05 ` Anisse Astier
2015-04-24 21:36 ` David Rientjes
2015-04-24 21:36 ` David Rientjes
2015-04-25 13:43 ` Anisse Astier
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 21:05 ` Anisse Astier
2015-04-24 21:38 ` David Rientjes
2015-04-24 21:38 ` David Rientjes
2015-04-25 13:52 ` Anisse Astier
2015-04-25 13:52 ` Anisse Astier
2015-04-26 20:12 ` Andi Kleen [this message]
2015-04-26 20:12 ` Andi Kleen
2015-04-27 8:11 ` Anisse Astier
2015-04-27 8:11 ` Anisse Astier
2015-04-27 9:25 ` PaX Team
2015-04-27 9:25 ` PaX Team
2015-04-27 21:27 ` Anisse Astier
2015-04-27 21:27 ` Anisse Astier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87tww2ejit.fsf@tassilo.jf.intel.com \
--to=andi@firstfloor.org \
--cc=akpm@linux-foundation.org \
--cc=anisse@astier.eu \
--cc=gnomes@lxorguk.ukuu.org.uk \
--cc=keescook@chromium.org \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=pageexec@freemail.hu \
--cc=peterz@infradead.org \
--cc=rientjes@google.com \
--cc=spender@grsecurity.net \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.