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Date: Tue, 9 Aug 2016 22:02:25 +0200 (CEST)
From: Jiri Kosina <jikos@kernel.org>
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To: "Rafael J. Wysocki" <rafael@kernel.org>
cc: Thomas Garnier <thgarnie@google.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
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        Kernel Hardening <kernel-hardening@lists.openwall.com>,
        Borislav Petkov <bpetkov@suse.de>
Subject: Re: [Resend][PATCH] x86/power/64: Always create temporary identity
 mapping correctly
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On Tue, 9 Aug 2016, Rafael J. Wysocki wrote:

> I have a murky suspicion, but it is really weird.  Namely, what if
> restore_jump_address in set_up_temporary_text_mapping() happens to be
> covered by the restore kernel's identity mapping?  Then, the image
> kernel's entry point may get overwritten by something else in
> core_restore_code().

So this made me to actually test a scenario where I'd suspend a kernel 
that's known-broken (i.e. contains 021182e52fe), and then have it resumed 
by a kernel that has 021182e52fe reverted. It resumed successfully.

Just a datapoint.

-- 
Jiri Kosina
SUSE Labs