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From: Richard Weinberger <richard@sigma-star.at>
To: Michal Hocko <mhocko@kernel.org>
Cc: Richard Weinberger <richard.weinberger@gmail.com>,
	Jefferson Carpenter <jeffersoncarpenter2@gmail.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Memory zeroed when made available to user process
Date: Wed, 27 Jun 2018 15:18:52 +0200	[thread overview]
Message-ID: <2634793.Cb5OrAPIO5@blindfold> (raw)
In-Reply-To: <20180627131248.GA3032@dhcp22.suse.cz>

Am Mittwoch, 27. Juni 2018, 15:12:48 CEST schrieb Michal Hocko:
> On Wed 27-06-18 13:29:05, Richard Weinberger wrote:
> > On Wed, Jun 27, 2018 at 11:34 AM, Jefferson Carpenter
> > <jeffersoncarpenter2@gmail.com> wrote:
> > > Is there a way for a user process to mark memory as 'sensitive' or
> > > 'non-sensitive' when it is allocated?  That could allow it not to have to be
> > > zeroed before being allocated to another process.
> > 
> > Isn't this what we have Meltdown and Spectre for? ;-)
> > 
> > No, memory from the kernel is always zeroed.
> > libc offers malloc() and calloc() for this purpose.
> 
> Well, except for the weird MAP_UNINITIALIZED. Anyway agreed that this is
> a bad idea and the flag should have never been merged. I've just
> mentioned it for completness.

Oh, I forgot about the crazy nommu world. :-)

Thanks,
//richard

-- 
sigma star gmbh - Eduard-Bodem-Gasse 6 - 6020 Innsbruck - Austria
ATU66964118 - FN 374287y

  reply	other threads:[~2018-06-27 13:19 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-27  9:34 Memory zeroed when made available to user process Jefferson Carpenter
2018-06-27 11:29 ` Richard Weinberger
2018-06-27 13:12   ` Michal Hocko
2018-06-27 13:18     ` Richard Weinberger [this message]
2018-06-29  0:52       ` Jefferson Carpenter
2018-06-29  6:10         ` Richard Weinberger

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