process creating gigabyte files on encrypted filesystem fails with 100% cpu

[William Anderson]

On my system, several programs that create gigabyte sized files fail. the process allocates around a gigabyte then goes into a state where no more data is written to the disk, but the process consumes 100% of the cpu.

this issue first lead to the reporting of bug #925309, where the process was unkillable. The unkillable part seems to be fixed in the latest kernel package 3.0.0-16-generic #29-Ubuntu, but the failure of the programs that caused this is still present.

this problem is not only in qemu-kvm, creating disk images in VirtualBox also triggers this problem, although i currently have the VirtualBox packages installed instead of the Ubuntu VirtualBox packages.

Both of these applications work with no problem when writing to a non-encrypted file system.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: qemu-kvm 0.14.1+noroms-0ubuntu6.2
ProcVersionSignature: Ubuntu 3.0.0-16.29-generic 3.0.20
Uname: Linux 3.0.0-16-generic i686
NonfreeKernelModules: wl
ApportVersion: 1.23-0ubuntu4
Architecture: i386
Date: Sun Mar 11 13:27:08 2012
EcryptfsInUse: Yes
ExecutablePath: /usr/bin/qemu-img
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
KvmCmdLine: Error: command ['ps', '-C', 'kvm', '-F'] failed with exit code 1: UID PID PPID C SZ RSS PSR STIME TTY TIME CMD
MachineType: LENOVO 2958
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, user)
 LANG=en_US.UTF-8
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-16-generic root=UUID=a6551c5d-43b4-4962-b132-0ddf59cb55ac ro crashkernel=384M-2G:64M,2G-:128M quiet splash vt.handoff=7
SourcePackage: qemu-kvm
UpgradeStatus: Upgraded to oneiric on 2012-01-14 (56 days ago)
dmi.bios.date: 05/05/2010
dmi.bios.vendor: LENOVO
dmi.bios.version: 18CN45WW(V2.54)
dmi.board.name: NITU1
dmi.board.vendor: LENOVO
dmi.board.version: REFERENCE
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: No Enclosure
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnLENOVO:bvr18CN45WW(V2.54):bd05/05/2010:svnLENOVO:pn2958:pvrLenovoG550:rvnLENOVO:rnNITU1:rvrREFERENCE:cvnNoEnclosure:ct10:cvrN/A:
dmi.product.name: 2958
dmi.product.version: Lenovo G550
dmi.sys.vendor: LENOVO

[Serge Hallyn (serge-hallyn)]

Do you also get failures when you do

   qemu-img create disk.img 10G
   kvm -hda disk.img -cdrom precise-amd64.iso

in other words, when not pre-allocating the image?

[William Anderson (william-anderson)]

if space is not pre-allocated the small image file is created with no trouble.

this problem has something to do with the writing of big files and have seen this in other applications including dd and transmission.

[William Anderson (william-anderson)]

This morning, when I checked the available updates in the update manager, I found a new kernel waiting to be installed. I upgraded to this kernel (version 3.0.0-17.30) and successfully booted into it with no problems.

william@ishtar:~$ uname -a
Linux ishtar 3.0.0-17-generic #30-Ubuntu SMP Thu Mar 8 17:34:21 UTC 2012 i686 i686 i386 GNU/Linux

After I booted into this kernel, I found that I was able to make big disk image files with both the qemu-img command and through the VirtualBox GUI. I was also able to interrupt the file creation process with ctl-c in the command window, or by pressing the cancel button in VirtualBox.

This issue seems to be fixed with this new kernel.

[William Anderson (william-anderson)]

upgraded to new kernel today with update manager. new kernel (version 3.0.0-19.33) works creating big disk image files on encrypted home directory with no trouble.

[Jakob Unterwurzacher (jakobunt)]

Setting to fix released as per your comment.