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Date:   Thu, 20 Sep 2018 11:39:17 +0200 (CEST)
From:   Thomas Gleixner <tglx@linutronix.de>
To:     Pu Wen <puwen@hygon.cn>
cc:     Rong Chen <rong.a.chen@intel.com>, bp@alien8.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
Subject: Re: [LKP] [x86/pci] 7ffb31888c: PANIC:early_exception
In-Reply-To: <7e9e862a-e890-775f-ed92-74c591c7deb6@hygon.cn>
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References: <20180919031923.GC8820@shao2-debian> <4f5166f8-97b8-a58f-3e5d-19d1751a4601@hygon.cn> <dfc09a36-cfc5-0479-a862-696c224f9a19@intel.com> <7e9e862a-e890-775f-ed92-74c591c7deb6@hygon.cn>
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On Thu, 20 Sep 2018, Pu Wen wrote:
> 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.

Return when !AMD and !HYGON is the right thing to do. No point in checking
device ids which cannot happen in the first place.

Thanks,

	tglx