linux-kernel - Re: KASLR causes intermittent boot failures on some systems

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Message-ID: <x498tn85k84.fsf@segfault.boston.devel.redhat.com>
Date:   Mon, 10 Apr 2017 11:57:15 -0400
From:   Jeff Moyer <jmoyer@...hat.com>
To:     Baoquan He <bhe@...hat.com>
Cc:     thgarnie@...gle.com, mingo@...nel.org, dan.j.williams@...el.com,
        linux-kernel@...r.kernel.org, linux-nvdimm@...ts.01.org
Subject: Re: KASLR causes intermittent boot failures on some systems

Baoquan He <bhe@...hat.com> writes:

> On 04/07/17 at 10:41am, Jeff Moyer wrote:
>> Hi,
>> 
>> commit 021182e52fe01 ("x86/mm: Enable KASLR for physical mapping memory
>> regions") causes some of my systems with persistent memory (whether real
>> or emulated) to fail to boot with a couple of different crash
>> signatures.  The first signature is a NMI watchdog lockup of all but 1
>> cpu, which causes much difficulty in extracting useful information from
>> the console.  The second variant is an invalid paging request, listed
>> below.
>> 
>> On some systems, I haven't hit this problem at all.  Other systems
>> experience a failed boot maybe 20-30% of the time.  To reproduce it,
>> configure some emulated pmem on your system.  You can find directions
>> for that here: https://nvdimm.wiki.kernel.org/
>
> I got below problem when configure ndctl, didn't find a package named
> libkmod:

Sorry, you can skip the ndctl step altogether.  This is emulated pmem,
so the setting won't stick anyway.

-Jeff