From: Michal Hocko <mhocko@kernel.org>
To: Richard Weinberger <richard.weinberger@gmail.com>
Cc: 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 15:12:48 +0200 [thread overview]
Message-ID: <20180627131248.GA3032@dhcp22.suse.cz> (raw)
In-Reply-To: <CAFLxGvyJsjWum34Q67UP+EGkg9+W0nPsMpu8mS9PaH8wL3Rd9g@mail.gmail.com>
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.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-06-27 13:12 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 [this message]
2018-06-27 13:18 ` Richard Weinberger
2018-06-29 0:52 ` Jefferson Carpenter
2018-06-29 6:10 ` Richard Weinberger
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