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Date:   Wed, 28 Nov 2018 09:57:54 +0800
From:   Baoquan He <bhe@redhat.com>
To:     Kees Cook <keescook@chromium.org>
Cc:     Borislav Petkov <bp@alien8.de>,
        Kazuhito Hagio <k-hagio@ab.jp.nec.com>,
        Bhupesh Sharma <bhsharma@redhat.com>, X86 ML <x86@kernel.org>,
        Kexec Mailing List <kexec@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Omar Sandoval <osandov@fb.com>,
        Dave Anderson <anderson@redhat.com>,
        James Morse <james.morse@arm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Bhupesh SHARMA <bhupesh.linux@gmail.com>,
        Ingo Molnar <mingo@kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2] x86_64, vmcoreinfo: Append 'page_offset_base' to
 vmcoreinfo
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On 11/27/18 at 04:39pm, Kees Cook wrote:
> >> >> diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
> >> >> index 4c8acdfdc5a7..6161d77c5bfb 100644
> >> >> --- a/arch/x86/kernel/machine_kexec_64.c
> >> >> +++ b/arch/x86/kernel/machine_kexec_64.c
> >> >> @@ -356,6 +356,9 @@ void arch_crash_save_vmcoreinfo(void)
> >> >>       VMCOREINFO_SYMBOL(init_top_pgt);
> >> >>       vmcoreinfo_append_str("NUMBER(pgtable_l5_enabled)=%d\n",
> >> >>                       pgtable_l5_enabled());
> >> >> +#ifdef CONFIG_RANDOMIZE_BASE
> 
> Okay, gotcha. In that case, shouldn't this be CONFIG_RANDOMIZE_MEMORY?

And yes, if we only care about KASLR, it should be
CONFIG_RANDOMIZE_MEMORY, but not CONFIG_RANDOMIZE_BASE.