[Bug 92291] New: kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

[Bug 92291] New: kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=92291

            Bug ID: 92291
           Summary: kvm/guest crashes when smp > 1 with AMD FX8300; with
                    host kernel oops from abrt as well
           Product: Virtualization
           Version: unspecified
    Kernel Version: 3.18.3-201.fc21.x86_64 [host], 3.13.0-39-generic
                    [ubuntu guest]
          Hardware: x86-64
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: high
          Priority: P1
         Component: kvm
          Assignee: virtualization_kvm@kernel-bugs.osdl.org
          Reporter: kernelbugzilla.org.Markie1@dfgh.net
        Regression: No

Created attachment 165171
  --> https://bugzilla.kernel.org/attachment.cgi?id=165171&action=edit
kvm register dumps

Overview
========
Whenever I launch a kvm guest in qemu-system-x86_64 with -smp > 1 [-cpu host
-enable-kvm of course], the guest kernel crashes at some stage; I've seen the
kernel crash before completing boot-up, giving the recognizable kernel crash
trace, as well as during 'normal' operation when the guest simply 'freezes'.
The host kernel gives me an oops as well, although abrt won't let me report it
now as I've got Nvidia proprietary drivers 'tainting' the kernel
The bug seems non-specific to guest OS, though mainly it's been *buntu guests,
with various different kernels including lowlatency, I even think I've seen the
bug with a Windows guest. I've tried building qemu from git sources, no
particularly noticeable difference;

Steps to reproduce
==================

1) Start linux guest on a multicore system [AMD FX8* series CPU?] with
$ qemu-system-x86_64 -m 2G -cpu host -smp 4 -enable-kvm -hda [image_file] -vga
vmware

2) wait until the guest kernel crashes; virtually every time in less than 10
minutes

Actual results
==============
guest kernel crashes, host kernel gives an oops too, presumably as a result of
kvm passthrough

Expected results
================
guest virtual machine should work normally then keep working normally

it would be good to try to pipe dmesg from the guest to the host serial
connection, in case that would assist?

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[Bug 92291] kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=92291

--- Comment #1 from Mark <kernelbugzilla.org.Markie1@dfgh.net> ---
Created attachment 165181
  --> https://bugzilla.kernel.org/attachment.cgi?id=165181&action=edit
serial log during bug; when smp > 1

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[Bug 92291] kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=92291

--- Comment #2 from Mark <kernelbugzilla.org.Markie1@dfgh.net> ---
Created attachment 165191
  --> https://bugzilla.kernel.org/attachment.cgi?id=165191&action=edit
serial log when no smp

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[Bug 92291] kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

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--- Comment #3 from Mark <kernelbugzilla.org.Markie1@dfgh.net> ---
Created attachment 165201
  --> https://bugzilla.kernel.org/attachment.cgi?id=165201&action=edit
host cpuinfo

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[Bug 92291] kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=92291

--- Comment #4 from Mark <kernelbugzilla.org.Markie1@dfgh.net> ---
I should just add that that 'code' segment in the kvm dump is identical every
time, I'd be happy to try to track what is causing it, providing someone could
give me some pointers to debugging that kind of stuff in more detail

Code=00 01 48 c7 c0 8a b0 00 00 31 db 0f b7 0c 01 b8 05 00 00 00 <0f> 01 c1 0f
1f 44 00 00 5b 41 5c 41 5d 41 5e 5d c3 89 f0 31 c9 f0 0f b0 0d fb 26 e6 00 40

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[Bug 92291] kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=92291

--- Comment #5 from Mark <kernelbugzilla.org.Markie1@dfgh.net> ---
Created attachment 166021
  --> https://bugzilla.kernel.org/attachment.cgi?id=166021&action=edit
result of guest lsmod; identical for mono-cpu / multi-cpu

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[Bug 92291] kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

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Alan <alan@lxorguk.ukuu.org.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |NEEDINFO
                 CC|                            |alan@lxorguk.ukuu.org.uk

--- Comment #6 from Alan <alan@lxorguk.ukuu.org.uk> ---
Can you reproduce it without the Nvidia blob loaded on the host ?

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[Bug 92291] kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

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Paolo Bonzini <bonzini@gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bonzini@gnu.org

--- Comment #7 from Paolo Bonzini <bonzini@gnu.org> ---
Your guest is probably missing commit c1118b3602c2329671ad5ec8bdf8e374323d6343.

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[Bug 92291] kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=92291

--- Comment #8 from Mark <kernelbugzilla.org.Markie1@dfgh.net> ---
Created attachment 166461
  --> https://bugzilla.kernel.org/attachment.cgi?id=166461&action=edit
dmesg

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[Bug 92291] kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

[bugzilla-daemon]

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--- Comment #9 from Mark <kernelbugzilla.org.Markie1@dfgh.net> ---
I'll try both of your suggestions, thanks

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[Bug 92291] kvm/guest crashes when smp > 1 with AMD FX8300; with host kernel oops from abrt as well

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=92291

--- Comment #10 from Mark <kernelbugzilla.org.Markie1@dfgh.net> ---
well thanks very much guys, I'll cautiously say that a patched guest kernel
seems to resolve it :-)

the bug seemed to appear even when the host is untainted; serial log says
[  375.989736] divide error: 0000 [#1] SMP 

that's a Kubuntu partition that manages without the proprietary drivers while
Fedora won't seem to give graphics properly with nouveau;

not entirely satisfactory of course given that I've now had to modify a virtual
machine that it was important to try to avoid modifying for testing purposes;
although definitely better than crashing :-)

do we keep the bug report open so that the host kvm handling bug gets fixed too
/ is this the right place to report that?

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