linux-kernel - Re: [PATCH v2] x86/smpboot: Make logical package management more robust

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Message-ID: <20170607121955.GA26412@chaos.hinterhof.net>
Date:   Wed, 7 Jun 2017 14:19:55 +0200
From:   Max Vozeler <max@...terhof.net>
To:     Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Borislav Petkov <bp@...en8.de>,
        "Charles (Chas) Williams" <ciwillia@...cade.com>,
        "M. Vefa Bicakci" <m.v.b@...box.com>,
        Alok Kataria <akataria@...are.com>,
        xen-devel <xen-devel@...ts.xen.org>,
        Juergen Groß <jgross@...e.com>,
        Thomas Weißschuh <kernel@...ssschuh.net>
Subject: Re: [PATCH v2] x86/smpboot: Make logical package management more
 robust

On Tue, Jun 06, 2017 at 09:48:37PM -0400, Boris Ostrovsky wrote:
> On 06/06/2017 09:39 AM, Max Vozeler wrote:
> >there is a problem booting recent kernels on some Xen domUs hosted by
> >provider JiffyBox.
> >
> >The kernel seems to crash just after logging
> >[    0.038700] SMP alternatives: switching to SMP code
> 
> Do you have the crash splat? Stack trace and such.
> 
> In fact, full boot log might be useful.

Unfortunately, we don't have much more information.

Just after "switching to SMP code" the console connection is lost and we
get a notification that the VM has crashed. I'm attaching the boot log up
to that point.. just in case.

I have asked the hosting provider if they can provide XEN hypervisor logs.

> >We started seeing this with 4.9.2 and bisecting the 4.9 stable kernels
> >determined that this commit introduced the problem. Reverting it from 4.9.2
> >makes the kernel boot again.
> >
> >Older kernels (starting from 3.16 up to and including 4.9.1) were running
> >fine in this setup. But recent mainline (tested 4.12-rc3) and 4.9.x both
> >fail to boot there.
> >
> >Unfortunately we have no detailed information about the hypervisor or
> >setup and the provider is not very forthcoming with details. I'm attaching
> >dmesg of a successful boot (4.9.2 with this commit reverted).
> >
> >It shows a fairly old XEN version:
> >
> >[    0.000000] Xen version: 3.1.2-416.el5 (preserve-AD)
> 
> This is a 10 year old hypervisor so it's not especially surprising that
> newer kernels don't work. (If anything, I am surprised that you actually
> booted 4.9 at all).
> 
> There have been a bunch of problems in this area (topology) on PV guests.

Thanks and kind regards,

	Max


View attachment "dmesg-crash.txt" of type "text/plain" (5992 bytes)