Public bug reported: mdadm 3.3-2ubuntu7.6 (for xenial) has a bug which may break an internal write-intent bitmap. Due to this bug, a bitmap overlaps with a bbl (bad block log), then the bbl gets to be inconsistent.
The cause of the bug is that a bbl is placed at a fixed location (80 sectors from the beginning of a disk). Because an internal write-intent bitmap is placed before the bbl (16 sectors from the beginning of a disk), it overlaps with the bbl when it grows too large (> 64 sectors). See this figure. https://cdn-ak.f.st- hatena.com/images/fotolife/u/uchan_nos/20171126/20171126111715.png This bug has been fixed in upstream of mdadm. The fixing commit is https://github.com/neilbrown/mdadm/commit/1b7eb672f7792313cc1517feaae8267575fc496b I tested the bug on the following versions: - mdadm 3.3-2ubuntu7.6 (for xenial) : The bug is reproduced - mdadm 3.4-4ubuntu0.1 (for zesty) : The bug is reproduced - mdadm 4.0-2 (for artful) : The bug has been fixed I want you to backport the patch to Ubuntu 16.04 LTS because the bug is serious. Detailed description (containing scripts to reproduce the bug) is here: https://gist.github.com/uchan-nos/4a4894f3c8e4a59ed0b870b5a516dcad#file-mdadm_bug_bbl_disruption-md ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: mdadm 3.3-2ubuntu7.2 ProcVersionSignature: Ubuntu 4.4.0-96.119-generic 4.4.83 Uname: Linux 4.4.0-96-generic x86_64 ApportVersion: 2.20.1-0ubuntu2.13 Architecture: amd64 Date: Thu Dec 14 18:09:57 2017 InstallationDate: Installed on 2017-02-03 (313 days ago) InstallationMedia: Ubuntu-Server 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719) Lspci: Lsusb: Error: command ['lsusb'] failed with exit code 1: MDadmExamine.dev.sda: Error: command ['/sbin/mdadm', '-E', '/dev/sda'] failed with exit code 1: mdadm: cannot open /dev/sda: Permission denied MDadmExamine.dev.sda1: Error: command ['/sbin/mdadm', '-E', '/dev/sda1'] failed with exit code 1: mdadm: cannot open /dev/sda1: Permission denied MDadmExamine.dev.sda2: Error: command ['/sbin/mdadm', '-E', '/dev/sda2'] failed with exit code 1: mdadm: cannot open /dev/sda2: Permission denied MDadmExamine.dev.sda3: Error: command ['/sbin/mdadm', '-E', '/dev/sda3'] failed with exit code 1: mdadm: cannot open /dev/sda3: Permission denied MDadmExamine.dev.sdb: Error: command ['/sbin/mdadm', '-E', '/dev/sdb'] failed with exit code 1: mdadm: cannot open /dev/sdb: Permission denied MDadmExamine.dev.sdb1: Error: command ['/sbin/mdadm', '-E', '/dev/sdb1'] failed with exit code 1: mdadm: cannot open /dev/sdb1: Permission denied MachineType: Microsoft Corporation Virtual Machine ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-96-generic root=/dev/mapper/hostname--vg-root ro rootflags=subvol=@ SourcePackage: mdadm UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 08/26/2016 dmi.bios.vendor: Microsoft Corporation dmi.bios.version: Hyper-V UEFI Release v2.0 dmi.board.asset.tag: None dmi.board.name: Virtual Machine dmi.board.vendor: Microsoft Corporation dmi.board.version: Hyper-V UEFI Release v2.0 dmi.chassis.asset.tag: 6099-8796-9610-2381-8579-4771-22 dmi.chassis.type: 3 dmi.chassis.vendor: Microsoft Corporation dmi.chassis.version: Hyper-V UEFI Release v2.0 dmi.modalias: dmi:bvnMicrosoftCorporation:bvrHyper-VUEFIReleasev2.0:bd08/26/2016:svnMicrosoftCorporation:pnVirtualMachine:pvrHyper-VUEFIReleasev2.0:rvnMicrosoftCorporation:rnVirtualMachine:rvrHyper-VUEFIReleasev2.0:cvnMicrosoftCorporation:ct3:cvrHyper-VUEFIReleasev2.0: dmi.product.name: Virtual Machine dmi.product.version: Hyper-V UEFI Release v2.0 dmi.sys.vendor: Microsoft Corporation etc.blkid.tab: Error: [Errno 2] No such file or directory: '/etc/blkid.tab' ** Affects: mdadm (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug third-party-packages xenial -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1738156 Title: mdadm may broke bbl if bitmap is too large To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/1738156/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
