kernel-hardening - Re: [Resend][PATCH] x86/power/64: Always create temporary identity mapping correctly

Follow @Openwall on Twitter for new release announcements and other news

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

Message-ID: <CAJZ5v0iAuDYZhmXqG12ZtEpQ5FEzP9Wp4a=EqApwwCc1VBvbLg@mail.gmail.com>
Date: Thu, 11 Aug 2016 02:35:48 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Jiri Kosina <jikos@...nel.org>, Thomas Garnier <thgarnie@...gle.com>
Cc: Borislav Petkov <bp@...e.de>, "Rafael J. Wysocki" <rjw@...ysocki.net>, 
	Linux PM list <linux-pm@...r.kernel.org>, "the arch/x86 maintainers" <x86@...nel.org>, 
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Yinghai Lu <yinghai@...nel.org>, 
	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, "H . Peter Anvin" <hpa@...or.com>, 
	Kees Cook <keescook@...omium.org>, Pavel Machek <pavel@....cz>, 
	Kernel Hardening <kernel-hardening@...ts.openwall.com>
Subject: Re: [Resend][PATCH] x86/power/64: Always create temporary identity
 mapping correctly

On Wed, Aug 10, 2016 at 11:59 PM, Jiri Kosina <jikos@...nel.org> wrote:
> On Wed, 10 Aug 2016, Rafael J. Wysocki wrote:
>
>> So I used your .config to generate one for my test machine and with
>> that I can reproduce.
>
> Was that the config I've sent, or did Boris provide one as well? Which one
> are you able to reproduce with please?

It's the Boris' one.

Moreover, I have found the options that make the difference: unsetting
CONFIG_PROVE_LOCKING and CONFIG_DEBUG_LOCK_ALLOC (which also will
unset CONFIG_LOCKDEP AFAICS) in it makes hibernation work again with
CONFIG_RANDOMIZE_MEMORY set and with the $subject patch applied.

Unbelievable, but that's what I'm seeing.

Now, that leads to a few questions:

- How does lockdep change the picture so it matters for hibernation?
- Why is hibernation the only piece that's affected?
- Why is RANDOMIZE_MEMORY necessary to make this breakage show up?

Thomas, any ideas?

Thanks,
Rafael

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.