linux-kernel - Re: [PATCH RFC] x86/cpu: fix intermittent lockup on poweroff

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Date:   Tue, 25 Apr 2023 15:58:21 -0400
From:   Tony Battersby <tonyb@...ernetics.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>,
        Mario Limonciello <mario.limonciello@....com>,
        Tom Lendacky <thomas.lendacky@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RFC] x86/cpu: fix intermittent lockup on poweroff

On 4/25/23 15:39, Borislav Petkov wrote:
> On Tue, Apr 25, 2023 at 03:26:53PM -0400, Tony Battersby wrote:
>> In stop_this_cpu(), make sure the CPUID leaf exists before accessing the
>> leaf.  This fixes a lockup on poweroff 50% of the time due to the wrong
>> branch being taken randomly on some CPUs (seen on Supermicro X8DTH-6F
>> with Intel Xeon X5650).
> Please send the output of
>
> cpuid -r
>
> from that machine.
>
> Thx.
>
I have attached the output for the Xeon X5650 and Xeon X5690 (one is
running a slightly older kernel).  I have two different systems with
Supermicro X8DTH-6F motherboards and different speed CPUs, and I have
seen the problem on both of them.

Tony Battersby
Cybernetics

View attachment "cpuid-X5650" of type "text/plain" (26966 bytes)

View attachment "cpuid-X5690" of type "text/plain" (26966 bytes)