linux-kernel - Re: [BUG] GPF on reboot of box

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Date:   Fri, 06 Oct 2017 23:13:13 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Nadav Amit <nadav.amit@...il.com>
CC:     LKML <linux-kernel@...r.kernel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [BUG] GPF on reboot of box

This bug still crashes my box on rc3

-- Steve


On October 6, 2017 10:21:26 PM EDT, Nadav Amit <nadav.amit@...il.com> wrote:
>Steven Rostedt <rostedt@...dmis.org> wrote:
>
>> Starting with v4.14-rc1 my box crashes during a reboot. All I get is
>> the following:
>> 
>> [  250.615793] sd 0:0:0:0: [sda] Synchronizing SCSI cache
>> [  250.635639] reboot: Restarting system
>> [  250.639671] reboot: machine restart
>> [  250.643842] general protection fault: 0000 [#1] PREEMPT SMP KASAN
>> 
>> Then nothing. No reboot, it just hangs there.
>> 
>> I bisected it down to this commit:
>> 
>> 660da7c9228f ("x86/mm: Enable CR4.PCIDE on supported systems")
>> 
>> If I comment out the setting of X86_CR4_PCIDE in that commit, it
>boots
>> fine. But...
>> 
>> I noticed that commit c7ad5ad29 ("x86/mm/64: Initialize CR4.PCIDE
>> early") moved the problem code from arch/x86/kernel/cpu/common.c to
>> arch/x86/mm/init.c
>> 
>> If I comment it out in v4.14-rc1, it crashes on boot up.
>> 
>> It appears that my box doesn't like having X86_CR4_PCIDE set. it
>causes
>> reboot to fail. But it also appears that setting that is required for
>> some other code to work.
>
>IIRC, there was a problem in rc1, which should be resolved in newer
>rcs.
>If you need to run rc1, you can try to use the kernel parameter
>“nopcid".
>
>Nadav

-- 
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