[Bug 1552752] Re: kernel bug when mounting a qemu-nbd backed image

The task "linux (Ubuntu)" has expired because it has had no new comments or updates for more than three years. If this issue is still present in an Ubuntu LTS kernel still under active support, please reopen the bug and provide updated details. If this issue was reported against an Ubuntu kernel no longer under active support but the issue still exists in a currently supported Ubuntu kernel, please open a new bug against that kernel version and provide the updated details, with a reference link to the original bug. This action was performed by an automated process maintained by the Ubuntu Kernel Team. ** Tags added: kernel-autoclosed kernel-autoclosed-expired ** Changed in: linux (Ubuntu) Status: Confirmed => Expired -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/1552752 Title: kernel bug when mounting a qemu-nbd backed image Status in linux package in Ubuntu: Expired Bug description: 1. % lsb_release -rd Description: Ubuntu 15.10 Release: 15.10 2. % apt-cache policy linux-image-generic linux-image-generic: Installed: (none) Candidate: 4.2.0.30.33 Version table: 4.2.0.30.33 0 500 http://us.archive.ubuntu.com/ubuntu/ wily-updates/main amd64 Packages 500 http://security.ubuntu.com/ubuntu/ wily-security/main amd64 Packages 4.2.0.16.18 0 500 http://us.archive.ubuntu.com/ubuntu/ wily/main amd64 Packages (kriek) ~ % apt-cache policy qemu-utils qemu-utils: Installed: 1:2.3+dfsg-5ubuntu9.2 Candidate: 1:2.3+dfsg-5ubuntu9.2 Version table: *** 1:2.3+dfsg-5ubuntu9.2 0 500 http://us.archive.ubuntu.com/ubuntu/ wily-updates/main amd64 Packages 500 http://security.ubuntu.com/ubuntu/ wily-security/main amd64 Packages 100 /var/lib/dpkg/status 1:2.3+dfsg-5ubuntu9 0 500 http://us.archive.ubuntu.com/ubuntu/ wily/main amd64 Packages 3. Configure an NBD device with a qemu image and then mount it. The base image is a wily amd64 cloud-image in raw format. Created the qcow2 device with: qemu-img create -f qcow2 -b /path/to/cloud-image.raw boot.img 2G Connect to nbd: sudo qemu-nbd -c /dev/nbd0 boot.img Mount it: sudo mount /dev/nbd0 /mnt Mount succeeds and I can examine the image. % qemu-img info --backing-chain boot.img image: boot.img file format: qcow2 virtual size: 2.0G (2147483648 bytes) disk size: 196K cluster_size: 65536 backing file: /srv/images/wily/amd64/20160218/vmtest.root-image Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false image: /srv/images/wily/amd64/20160218/vmtest.root-image file format: raw virtual size: 1.4G (1468006400 bytes) disk size: 1.4G 4. mount command hung and kernel emitted BUG(). In reproducing this may be relevant. a. Configure NBD with boot.img as in (3) b. while still mounted rm boot.img c. disconnect: qemu-nbd -d /dev/nbd0 d. unmount: umount /mnt Then repeat (3). ProblemType: Bug DistroRelease: Ubuntu 15.10 Package: linux-image-4.2.0-19-generic 4.2.0-19.23 ProcVersionSignature: Ubuntu 4.2.0-19.23-generic 4.2.6 Uname: Linux 4.2.0-19-generic x86_64 AlsaVersion: Advanced Linux Sound Architecture Driver Version k4.2.0-19-generic. AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.19.1-0ubuntu5 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/by-path', '/dev/snd/hwC0D3', '/dev/snd/pcmC0D8p', '/dev/snd/pcmC0D7p', '/dev/snd/pcmC0D3p', '/dev/snd/controlC0', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: Card0.Amixer.info: Error: [Errno 2] No such file or directory: 'amixer' Card0.Amixer.values: Error: [Errno 2] No such file or directory: 'amixer' Date: Thu Mar 3 09:18:14 2016 HibernationDevice: RESUME=/dev/mapper/kriek--vg-swap_1 InstallationDate: Installed on 2015-05-10 (297 days ago) InstallationMedia: Ubuntu-Server 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.3) ProcEnviron: TERM=xterm PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.2.0-19-generic root=/dev/mapper/hostname--vg-root ro nomdmonddf nomdmonisw RelatedPackageVersions: linux-restricted-modules-4.2.0-19-generic N/A linux-backports-modules-4.2.0-19-generic N/A linux-firmware 1.149.3 RfKill: Error: [Errno 2] No such file or directory: 'rfkill' SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 11/05/2014 dmi.bios.vendor: Intel Corp. dmi.bios.version: RKPPT10H.86A.0037.2014.1105.1813 dmi.board.asset.tag: To be filled by O.E.M. dmi.board.name: D53427RKE dmi.board.vendor: Intel Corporation dmi.board.version: G87971-406 dmi.chassis.type: 3 dmi.modalias: dmi:bvnIntelCorp.:bvrRKPPT10H.86A.0037.2014.1105.1813:bd11/05/2014:svn:pn:pvr:rvnIntelCorporation:rnD53427RKE:rvrG87971-406:cvn:ct3:cvr: To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1552752/+subscriptions