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From: Thomas Garnier <thgarnie@google.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Borislav Petkov <bp@suse.de>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
	Linux PM <linux-pm@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	Jiri Kosina <jikos@kernel.org>, Yinghai Lu <yinghai@kernel.org>
Subject: Re: [PATCH v1] x86/power/64: Restore processor state before using per-cpu variables
Date: Fri, 12 Aug 2016 09:03:52 -0700	[thread overview]
Message-ID: <CAJcbSZEAyS6Lp=Cuz=-4yL39yz=Z_FpVuY2NiYjM=fchFtpTEg@mail.gmail.com> (raw)
In-Reply-To: <CAJZ5v0hC28BMqgurck0oiQGxf=XhYwseiVs+DeLdv9wKHFCa7w@mail.gmail.com>

On Fri, Aug 12, 2016 at 4:14 AM, Rafael J. Wysocki <rafael@kernel.org> wrote:
> On Fri, Aug 12, 2016 at 7:49 AM, Borislav Petkov <bp@suse.de> wrote:
>> On Thu, Aug 11, 2016 at 02:49:29PM -0700, Thomas Garnier wrote:
>>> Restore the processor state before calling any other function to ensure
>>> per-cpu variables can be used with KASLR memory randomization.
>>>
>>> Tracing functions use per-cpu variables (gs based) and one was called
>>> just before restoring the processor state fully. It resulted in a double
>>> fault when both the tracing & the exception handler functions tried to
>>> use a per-cpu variable.
>>>
>>> Signed-off-by: Thomas Garnier <thgarnie@google.com>
>>> ---
>>> Based on next-20160808
>>
>> Ok, I believe before I test this, I need to apply another patch from
>> Rafael. I think it is the "Always create temporary identity mapping
>> correctly" thing.
>>
>> Yes, no?
>
> Yes.
>
>> Rafael, can you please apply everything on a test branch for us to run?
>
> You can simply test my linux-next branch:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git \
> linux-next
>
> That's 4.8-rc1 plus 3 fixes on top of it.

Borislav, let me know once you tested it and I will send a v2 with acked/tested.

WARNING: multiple messages have this Message-ID (diff)
From: Thomas Garnier <thgarnie@google.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Borislav Petkov <bp@suse.de>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
	Linux PM <linux-pm@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	Jiri Kosina <jikos@kernel.org>, Yinghai Lu <yinghai@kernel.org>
Subject: [kernel-hardening] Re: [PATCH v1] x86/power/64: Restore processor state before using per-cpu variables
Date: Fri, 12 Aug 2016 09:03:52 -0700	[thread overview]
Message-ID: <CAJcbSZEAyS6Lp=Cuz=-4yL39yz=Z_FpVuY2NiYjM=fchFtpTEg@mail.gmail.com> (raw)
In-Reply-To: <CAJZ5v0hC28BMqgurck0oiQGxf=XhYwseiVs+DeLdv9wKHFCa7w@mail.gmail.com>

On Fri, Aug 12, 2016 at 4:14 AM, Rafael J. Wysocki <rafael@kernel.org> wrote:
> On Fri, Aug 12, 2016 at 7:49 AM, Borislav Petkov <bp@suse.de> wrote:
>> On Thu, Aug 11, 2016 at 02:49:29PM -0700, Thomas Garnier wrote:
>>> Restore the processor state before calling any other function to ensure
>>> per-cpu variables can be used with KASLR memory randomization.
>>>
>>> Tracing functions use per-cpu variables (gs based) and one was called
>>> just before restoring the processor state fully. It resulted in a double
>>> fault when both the tracing & the exception handler functions tried to
>>> use a per-cpu variable.
>>>
>>> Signed-off-by: Thomas Garnier <thgarnie@google.com>
>>> ---
>>> Based on next-20160808
>>
>> Ok, I believe before I test this, I need to apply another patch from
>> Rafael. I think it is the "Always create temporary identity mapping
>> correctly" thing.
>>
>> Yes, no?
>
> Yes.
>
>> Rafael, can you please apply everything on a test branch for us to run?
>
> You can simply test my linux-next branch:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git \
> linux-next
>
> That's 4.8-rc1 plus 3 fixes on top of it.

Borislav, let me know once you tested it and I will send a v2 with acked/tested.

  reply	other threads:[~2016-08-12 16:04 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-11 21:49 [PATCH v1] x86/power/64: Restore processor state before using per-cpu variables Thomas Garnier
2016-08-11 21:49 ` [kernel-hardening] " Thomas Garnier
2016-08-12  5:49 ` Borislav Petkov
2016-08-12  5:49   ` [kernel-hardening] " Borislav Petkov
2016-08-12 11:14   ` Rafael J. Wysocki
2016-08-12 11:14     ` [kernel-hardening] " Rafael J. Wysocki
2016-08-12 16:03     ` Thomas Garnier [this message]
2016-08-12 16:03       ` Thomas Garnier
2016-08-12 17:45       ` Borislav Petkov
2016-08-12 17:45         ` [kernel-hardening] " Borislav Petkov
2016-08-12  6:01 ` Jiri Kosina
2016-08-12  6:01   ` [kernel-hardening] " Jiri Kosina
2016-08-12  9:23   ` Jiri Kosina
2016-08-12  9:23     ` [kernel-hardening] " Jiri Kosina
2016-08-12 16:03     ` Thomas Garnier
2016-08-12 16:03       ` [kernel-hardening] " Thomas Garnier
2016-08-12  6:29 ` Pavel Machek
2016-08-12  6:29   ` [kernel-hardening] " Pavel Machek

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