linux-kernel - Re: [RFC v1 2/2] mm: SLUB Freelist randomization

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAJcbSZFhsZheqdZ5FD8auhiu8ozCyq-0xY1wjYu3j+Wc2R8nGg@mail.gmail.com>
Date:	Wed, 18 May 2016 11:34:58 -0700
From:	Thomas Garnier <thgarnie@...gle.com>
To:	Christoph Lameter <cl@...ux.com>
Cc:	Pekka Enberg <penberg@...nel.org>,
	David Rientjes <rientjes@...gle.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>,
	Pranith Kumar <bobby.prani@...il.com>,
	David Howells <dhowells@...hat.com>, Tejun Heo <tj@...nel.org>,
	Johannes Weiner <hannes@...xchg.org>,
	David Woodhouse <David.Woodhouse@...el.com>,
	Petr Mladek <pmladek@...e.com>,
	Kees Cook <keescook@...omium.org>,
	Linux-MM <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Greg Thelen <gthelen@...gle.com>,
	kernel-hardening@...ts.openwall.com
Subject: Re: [RFC v1 2/2] mm: SLUB Freelist randomization

Yes, I agree that it is not related to the changes.

On Wed, May 18, 2016 at 11:24 AM, Christoph Lameter <cl@...ux.com> wrote:
> 0.On Wed, 18 May 2016, Thomas Garnier wrote:
>
>> slab_test, before:
>> 10000 times kmalloc(8) -> 67 cycles kfree -> 101 cycles
>> 10000 times kmalloc(16) -> 68 cycles kfree -> 109 cycles
>> 10000 times kmalloc(32) -> 76 cycles kfree -> 119 cycles
>> 10000 times kmalloc(64) -> 88 cycles kfree -> 114 cycles
>
>> After:
>> 10000 times kmalloc(8) -> 60 cycles kfree -> 74 cycles
>> 10000 times kmalloc(16) -> 63 cycles kfree -> 78 cycles
>> 10000 times kmalloc(32) -> 72 cycles kfree -> 85 cycles
>> 10000 times kmalloc(64) -> 91 cycles kfree -> 99 cycles
>
> Erm... The fastpath was not touched and the tests primarily exercise the
> fastpath. This is likely some artifact of code placement by the compiler?
>