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Date: Fri, 8 Aug 2014 13:43:01 +0100
From: David Vrabel <david.vrabel@citrix.com>
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To: Stefan Bader <stefan.bader@canonical.com>,
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CC: Kees Cook <keescook@chromium.org>, David Vrabel <david.vrabel@citrix.com>
Subject: Re: [Xen-devel] Xen PV domain regression with KASLR enabled (kernel
 3.16)
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On 08/08/14 12:20, Stefan Bader wrote:
> Unfortunately I have not yet figured out why this happens, but can confirm by
> compiling with or without CONFIG_RANDOMIZE_BASE being set that without KASLR all
> is ok, but with it enabled there are issues (actually a dom0 does not even boot
> as a follow up error).
> 
> Details can be seen in [1] but basically this is always some portion of a
> vmalloc allocation failing after hitting a freshly allocated PTE space not being
> PTE_NONE (usually from a module load triggered by systemd-udevd). In the
> non-dom0 case this repeats many times but ends in a guest that allows login. In
> the dom0 case there is a more fatal error at some point causing a crash.
> 
> I have not tried this for a normal PV guest but for dom0 it also does not help
> to add "nokaslr" to the kernel command-line.

Maybe it's overlapping with regions of the virtual address space
reserved for Xen?  What the the VA that fails?

David