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From:   Pu Wen <puwen@hygon.cn>
Subject: Re: [LKP] [x86/pci] 7ffb31888c: PANIC:early_exception
To:     Rong Chen <rong.a.chen@intel.com>
Cc:     bp@alien8.de, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
        x86@kernel.org, thomas.lendacky@amd.com, helgaas@kernel.org,
        linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
        linux-pci@vger.kernel.org, lkp@01.org
References: <20180919031923.GC8820@shao2-debian>
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Message-ID: <7e9e862a-e890-775f-ed92-74c591c7deb6@hygon.cn>
Date:   Thu, 20 Sep 2018 16:47:19 +0800
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On 2018/9/20 8:26, Rong Chen wrote:
> On 09/19/2018 09:53 PM, Pu Wen wrote:
>> I cannot reproduce this panic on Hygon Dhyana platform. I tired lkp-tests
>> both in Ubuntu 16.04 (with gcc-5) and Ubuntu 18.04 (with gcc-7).
>> What kind of host do you use to run the qemu? A Intel one or AMD one?
> It's a Intel one,
> 
> model: Nehalem-EX
> memory: 224G
> nr_node: 4
> nr_cpu: 64
> nr_socket: 4
> brand: Intel(R) Xeon(R) CPU X7560 @ 2.27GHz

I reproduced the PANIC by running lkp-tests with a Intel machine.

The reason is that the function early_is_amd_nb is called even if
running on Intel machine. At this case the misc_ids is NULL so the
PANIC occur.

I'll rework a patch to solve this problem, either restore the default
value of misc_ids with the original AMD one or not call early_is_amd_nb
on Intel platform.

-- 
Regards,
Pu Wen