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Date:   Tue, 17 Apr 2018 18:28:01 +0300
From:   Aaro Koskinen <aaro.koskinen@nokia.com>
To:     Dave Hansen <dave.hansen@linux.intel.com>,
        Ingo Molnar <mingo@kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: 4.17-rc1: early boot crash on x86_64 & pti
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Hi,

On Tue, Apr 17, 2018 at 06:01:30PM +0300, Aaro Koskinen wrote:
> I'm getting early crash on x86_64 box with 4.17-rc1 and PTI
> enabled. Bisected to:
> 
> commit 39114b7a743e6759bab4d96b7d9651d44d17e3f9
> Author: Dave Hansen <dave.hansen@linux.intel.com>
> Date:   Fri Apr 6 13:55:17 2018 -0700
> 
>     x86/pti: Never implicitly clear _PAGE_GLOBAL for kernel image

[...]

> [    0.000000] Kernel/User page tables isolation: enabled
> [    0.000000] ------------[ cut here ]------------
> [    0.000000] CPA: called for zero pte. vaddr = ffffffff8d000000 cpa->vaddr = ffffffff8d000000
> [    0.000000] WARNING: CPU: 0 PID: 0 at arch/x86/mm/pageattr.c:1189 __cpa_process_fault+0x4d6/0x510

I started enabling more .config options, and it seems that enabling
CONFIG_XEN_PV does some magic to make booting work... But I shouldn't
need it.

A.