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Date: Thu, 10 Nov 2016 13:46:34 +0100
From: Borislav Petkov <bp@alien8.de>
To: kernel test robot <xiaolong.ye@intel.com>
Cc: lkp@01.org, LKML <linux-kernel@vger.kernel.org>,
        X86 ML <x86@kernel.org>, linux-edac <linux-edac@vger.kernel.org>,
        "Luck, Tony" <tony.luck@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [x86/MCE]  81aa021b8c: WARNING: CPU: 0 PID: 0 at
 arch/x86/kernel/cpu/mcheck/mce.c:716 machine_check_poll+0x66/0x21c
Message-ID: <20161110124633.3fv4mc4kxvdxmnzj@pd.tnic>
References: <582469b2.PLOtWbwTF/l9zaTD%xiaolong.ye@intel.com>
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On Thu, Nov 10, 2016 at 08:36:02PM +0800, kernel test robot wrote:
> FYI, we noticed the following commit:
> 
> https://github.com/0day-ci/linux Borislav-Petkov/x86-MCE-Correct-TSC-timestamping-of-error-records/20161110-021431
> commit 81aa021b8c6f464b68c6e6df93e64ffe2c2adda6 ("x86/MCE: Remove MCP_TIMESTAMP")
> 
> in testcase: boot
> 
> on test machine: qemu-system-x86_64 -enable-kvm -m 320M
> 
> caused below changes:
> 
> 
> +-----------------------------------------------------------------+------------+------------+
> |                                                                 | b2eca63145 | 81aa021b8c |
> +-----------------------------------------------------------------+------------+------------+
> | boot_successes                                                  | 16         | 0          |
> | boot_failures                                                   | 0          | 10         |
> | WARNING:at_arch/x86/kernel/cpu/mcheck/mce.c:#machine_check_poll | 0          | 10         |
> +-----------------------------------------------------------------+------------+------------+
> 
> 
> 
> [    0.238462] Mountpoint-cache hash table entries: 1024 (order: 1, 8192 bytes)
> [    0.240536] mce: CPU supports 10 MCE banks
> [    0.241403] ------------[ cut here ]------------
> [    0.242334] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/cpu/mcheck/mce.c:716 machine_check_poll+0x66/0x21c
> [    0.244554] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.0-rc4-00300-g81aa021 #64
> [    0.246089] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
> [    0.247857] Call Trace:
> [    0.248341]  dump_stack+0x61/0x7e
> [    0.249018]  __warn+0xb3/0xce
> [    0.249594]  warn_slowpath_null+0x18/0x1a

Thanks guys, this actually helps!

I'll remove the WARN_ON_ONCE as it confirms a theory we had.

-- 
Regards/Gruss,
    Boris.

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