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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Ian Jackson <ijackson@chiark.greenend.org.uk>,
	Greg KH <gregkh@suse.de>, Ian Campbell <ijc@hellion.org.uk>,
	linux-kernel@vger.kernel.org, stable@kernel.org,
	stable-review@kernel.org, akpm@linux-foundation.org,
	alan@lxorguk.ukuu.org.uk
Subject: Re: [RFC] mlock/stack guard interaction fixup
Date: Mon, 23 Aug 2010 12:54:09 -0700	[thread overview]
Message-ID: <4C72D1E1.1040709@goop.org> (raw)
In-Reply-To: <1282591592.2605.2221.camel@laptop>

 On 08/23/2010 12:26 PM, Peter Zijlstra wrote:
> On Mon, 2010-08-23 at 12:23 -0700, Jeremy Fitzhardinge wrote:
>> On 08/23/2010 12:07 PM, Peter Zijlstra wrote:
>>> mlock() simply avoids major faults, nothing more.
>>>
>>> I think both page migration and page-out for shared pages where some
>>> maps are !mlocked can cause unmaps and thus minor faults.
>>>
>>> mlock and dirty do not interact, they will still be cleaned/written out
>>> as normal.
>> So mlock is useless for preventing secret stuff from being written to disk.
> Well, if you put your sekrit in a file map, sure.
>
> Use a mmap(MAP_ANONYMOUS|MAP_LOCK) and madvise(MADV_DONTFORK) for your
> sekrits.

Won't dirty anonymous pages also get written to swap?

    J

  reply	other threads:[~2010-08-23 19:54 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-20 23:59 [RFC] mlock/stack guard interaction fixup Linus Torvalds
2010-08-21  0:20 ` Mike Snitzer
2010-08-21  0:54   ` Linus Torvalds
2010-08-21 11:56 ` Ian Campbell
2010-08-21 15:48   ` Linus Torvalds
2010-08-21 16:08     ` Sam Ravnborg
2010-08-23 16:34       ` Tony Luck
2010-08-22  6:57     ` Ian Campbell
2010-08-22  7:33       ` Ian Campbell
2010-08-22  9:55         ` Ian Campbell
2010-08-22 16:43           ` Linus Torvalds
2010-08-22 17:25           ` Greg KH
2010-08-22 18:21             ` Linus Torvalds
2010-08-22 19:04               ` Greg KH
2010-08-23  9:22               ` Peter Zijlstra
2010-08-23 15:42               ` ijackson
2010-08-23 16:25                 ` Peter Zijlstra
2010-08-23 17:18                   ` Ian Jackson
2010-08-23 17:34                     ` Linus Torvalds
2010-08-23 17:53                       ` Peter Zijlstra
2010-08-23 17:59                       ` Peter Zijlstra
2010-08-23 18:43                         ` Darren Hart
2010-08-23 18:50                       ` Jeremy Fitzhardinge
2010-08-23 19:07                         ` Peter Zijlstra
2010-08-23 19:23                           ` Jeremy Fitzhardinge
2010-08-23 19:26                             ` Peter Zijlstra
2010-08-23 19:54                               ` Jeremy Fitzhardinge [this message]
2010-08-24  7:08                                 ` Peter Zijlstra
2010-08-24  7:20                                   ` Peter Zijlstra
2010-08-23 19:03                       ` Ian Campbell
2010-08-23 17:40                     ` Peter Zijlstra
2010-08-23 18:53                     ` Jeremy Fitzhardinge
2010-08-25  8:28             ` [Stable-review] " Stefan Bader
2010-08-23  9:00 ` Peter Zijlstra

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