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Re: [PATCH v1] x86/power/64: Restore processor state before using per-cpu variables

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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.

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[PATCH v1] x86/power/64: Restore processor state before using per-cpu variables Thomas Garnier <thgarnie@google.com> - 2016-08-12 00:00 +0200
  Re: [PATCH v1] x86/power/64: Restore processor state before using  per-cpu variables Borislav Petkov <bp@suse.de> - 2016-08-12 08:00 +0200
    Re: [PATCH v1] x86/power/64: Restore processor state before using  per-cpu variables "Rafael J. Wysocki" <rafael@kernel.org> - 2016-08-12 13:20 +0200
      Re: [PATCH v1] x86/power/64: Restore processor state before using  per-cpu variables Thomas Garnier <thgarnie@google.com> - 2016-08-12 18:10 +0200
        Re: [PATCH v1] x86/power/64: Restore processor state before using  per-cpu variables Borislav Petkov <bp@suse.de> - 2016-08-12 19:50 +0200
  Re: [PATCH v1] x86/power/64: Restore processor state before using  per-cpu variables Jiri Kosina <jikos@kernel.org> - 2016-08-12 08:10 +0200
    Re: [PATCH v1] x86/power/64: Restore processor state before using  per-cpu variables Jiri Kosina <jikos@kernel.org> - 2016-08-12 11:30 +0200
      Re: [PATCH v1] x86/power/64: Restore processor state before using  per-cpu variables Thomas Garnier <thgarnie@google.com> - 2016-08-12 18:10 +0200
  Re: [PATCH v1] x86/power/64: Restore processor state before using  per-cpu variables Pavel Machek <pavel@denx.de> - 2016-08-12 08:30 +0200

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