Null pointer dereference in mmu_set_spte.isra on 3.8.0-33-generic

[Pierre Schweitzer]

Dear all,

We faced a kernel oops on KVM from a null pointer derefence on one of our hypervisors (running several KVM VMs). This led us to a serie of kernel oops affecting all the VMs and finally, the host crash. We couldn't really establish where from the first oops was comming (in order to reproduce the crash).

You'll find attach the extract of syslog where you have the really first oops, and all the followings.

We're using Ubuntu 12.04LTS. We're using latest releases available on it, including for KVM. We're using kernel 3.8 due to hardware constraints. And we're using kernel 3.8.0-33-generic due to regressions in newer kernels (not yet reported).
---
AlsaDevices:
 total 0
 crw-rw---T 1 root audio 116, 1 Aug 4 14:07 seq
 crw-rw---T 1 root audio 116, 33 Aug 4 14:07 timer
AplayDevices: Error: [Errno 2] No such file or directory
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211 not found.
DistroRelease: Ubuntu 12.04
HibernationDevice: RESUME=UUID=27b2f2d3-0ec2-4f22-9f6d-c857b6830ab6
InstallationMedia:

IwConfig: Error: [Errno 2] No such file or directory
MachineType: MSI MS-7816
MarkForUpload: True
Package: linux (not installed)
PciMultimedia:

ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.8.0-33-generic root=UUID=4ee4d8b4-6b60-4800-b449-a22259277145 ro quiet elevator=deadline
ProcVersionSignature: Ubuntu 3.8.0-33.48~precise1-generic 3.8.13.11
RelatedPackageVersions:
 linux-restricted-modules-3.8.0-33-generic N/A
 linux-backports-modules-3.8.0-33-generic N/A
 linux-firmware 1.79.16
RfKill: Error: [Errno 2] No such file or directory
Tags: precise
Uname: Linux 3.8.0-33-generic x86_64
UpgradeStatus: Upgraded to precise on 2012-05-10 (817 days ago)
UserGroups:

WifiSyslog:
 Aug 5 06:25:17 rose kernel: [58628.862288] device eth0 left promiscuous mode
 Aug 5 06:25:33 rose kernel: [58644.253374] device eth0 entered promiscuous mode
dmi.bios.date: 08/23/2013
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: V2.14B6
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: H87-G43 (MS-7816)
dmi.board.vendor: MSI
dmi.board.version: 1.0
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: MSI
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrV2.14B6:bd08/23/2013:svnMSI:pnMS-7816:pvr1.0:rvnMSI:rnH87-G43(MS-7816):rvr1.0:cvnMSI:ct3:cvr1.0:
dmi.product.name: MS-7816
dmi.product.version: 1.0
dmi.sys.vendor: MSI

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1352794

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Pierre Schweitzer (pierre-jean-schweitzer)]

apport information

[Pierre Schweitzer (pierre-jean-schweitzer)]

apport information

[Pierre Schweitzer (pierre-jean-schweitzer)]

apport information

[Pierre Schweitzer (pierre-jean-schweitzer)]

apport information

[Pierre Schweitzer (pierre-jean-schweitzer)]

apport information

[Pierre Schweitzer (pierre-jean-schweitzer)]

apport information

[Pierre Schweitzer (pierre-jean-schweitzer)]

apport information

[Pierre Schweitzer (pierre-jean-schweitzer)]

apport information

[Pierre Schweitzer (pierre-jean-schweitzer)]

apport information

[Pierre Schweitzer (pierre-jean-schweitzer)]

apport information

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.16 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.16-utopic/

[Pierre Schweitzer (pierre-jean-schweitzer)]

We cannot unfortunately test upstream kernel due to a regression in recent kernels we couldn't track yet (in connections bridging). Furthermore, this crash happened only once in several months in production. And finally, this is a production server on which we're pretty not willing doing tests. It has to remain stable.