checkarray doesn't work

Bug #1599428 reported by Simon Déziel on 2016-07-06
This bug affects 3 people
Affects Status Importance Assigned to Milestone
mdadm (Debian)
Fix Released
mdadm (Ubuntu)
Dimitri John Ledkov

Bug Description

Problem description:

The script /usr/share/mdadm/checkarray exits before checking any array.

Steps to reproduce:

1) Check the status of every arrays
  /usr/share/mdadm/checkarray --all --status
2) Expected output
    md0: idle
3) Problematic output: nothing

Additional information:

When I tried to manually check my RAID1 array with "/usr/share/mdadm/checkarray --all --status" I noticed it produced no output. When I invoked it with "sh -x" and the same parameters as the monthly checking cron job I noticed it was exiting early, before performing any real check.

# sh -x /usr/share/mdadm/checkarray --cron --all --idle --quiet
+ [ 1 = 1 ]
+ + ls -d1 /sys/block/md0
cut -d/ -f4
+ arrays=md0
+ MDBASE=/sys/block/md0/md
+ [ ! -e /sys/block/md0/md/sync_action ]
+ read cur_status

Under Xenial, dash doesn't seem to like this instruction:

 read cur_status < $MDBASE/sync_action

Oddly enough, it works just fine with Trusty's dash.

Software versions:

# lsb_release -rd
Description: Ubuntu 16.04 LTS
Release: 16.04
# apt-cache policy mdadm dash
  Installed: 3.3-2ubuntu7.1
  Candidate: 3.3-2ubuntu7.1
  Version table:
 *** 3.3-2ubuntu7.1 500
        500 xenial-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     3.3-2ubuntu7 500
        500 xenial/main amd64 Packages
  Installed: 0.5.8-2.1ubuntu2
  Candidate: 0.5.8-2.1ubuntu2
  Version table:
 *** 0.5.8-2.1ubuntu2 500
        500 xenial/main amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: mdadm 3.3-2ubuntu7.1
ProcVersionSignature: Ubuntu 4.4.0-28.47-generic 4.4.13
Uname: Linux 4.4.0-28-generic x86_64
NonfreeKernelModules: zfs zunicode zcommon znvpair zavl
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: Unity
CurrentDmesg: Error: command ['dmesg'] failed with exit code 1: dmesg: read kernel buffer failed: Operation not permitted
Date: Wed Jul 6 04:36:29 2016 Error: command ['/sbin/mdadm', '-E', '/dev/sda'] failed with exit code 1: mdadm: cannot open /dev/sda: Permission denied Error: command ['/sbin/mdadm', '-E', '/dev/sda1'] failed with exit code 1: mdadm: cannot open /dev/sda1: Permission denied Error: command ['/sbin/mdadm', '-E', '/dev/sda2'] failed with exit code 1: mdadm: cannot open /dev/sda2: Permission denied
MachineType: LENOVO 2516CTO
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-28-generic root=/dev/mapper/crypt-xroot ro quiet splash cryptopts=target=crypt,source=/dev/sda1,lvm=crypt-xroot possible_cpus=4 nmi_watchdog=0 kaslr vt.handoff=7
 Personalities :
 unused devices: <none>
SourcePackage: mdadm
UpgradeStatus: No upgrade log present (probably fresh install) 02/14/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: 6IET85WW (1.45 ) 2516CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr6IET85WW(1.45):bd02/14/2013:svnLENOVO:pn2516CTO:pvrThinkPadT410:rvnLENOVO:rn2516CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable: 2516CTO
dmi.product.version: ThinkPad T410
dmi.sys.vendor: LENOVO Error: [Errno 2] No such file or directory: '/etc/'
modified.conffile..etc.logcheck.ignore.d.server.mdadm: [deleted]
modified.conffile..etc.logcheck.violations.d.mdadm: [deleted]

Simon Déziel (sdeziel) wrote :
Simon Déziel (sdeziel) wrote :

After some more debugging, it seems to be a behavior change in dash between Xenial:

# /bin/sh -c 'read cur_status < /sys/block/md0/md/sync_action; echo $cur_status'
# /bin/bash -c 'read cur_status < /sys/block/md0/md/sync_action; echo $cur_status'

And Trusty:

# /bin/sh -c 'read cur_status < /sys/block/md0/md/sync_action; echo $cur_status'
# /bin/bash -c 'read cur_status < /sys/block/md0/md/sync_action; echo $cur_status'

Simon Déziel (sdeziel) wrote :
Simon Déziel (sdeziel) wrote :

According to, this is a combination of how dash reads files and the kernel version (4.0+).

If that's true, even Trusty machines could be affected when running the HWE kernels.

Simon Déziel (sdeziel) wrote :

A kernel side fix was proposed ( but remains to be merged upstream.

The attachment "Workaround for Xenial's dash" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

tags: added: patch
Changed in mdadm (Debian):
status: Unknown → New
Changed in mdadm (Ubuntu):
assignee: nobody → Mathieu Trudel-Lapierre (cyphermox)
Changed in mdadm (Ubuntu):
status: New → Triaged
importance: Undecided → High
Changed in mdadm (Ubuntu):
assignee: Mathieu Trudel-Lapierre (cyphermox) → Dimitri John Ledkov (xnox)
Changed in mdadm (Ubuntu):
status: Triaged → Fix Committed
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package mdadm - 4.0-1

mdadm (4.0-1) unstable; urgency=medium

  * New upstream release. LP: #1668128
  * Drop warnings that raid arrays are missing from the initramfs
    configuration. Instead have a positive message as to which arrays are
    included in the initramfs.
  * Add a warning to mkconf generated file that mdadm.conf is copied into
  * Fix checkarray script bugs. LP: #1599428 Closes: #787950 Closes: #843665

 -- Dimitri John Ledkov <email address hidden> Thu, 22 Jun 2017 13:23:10 +0100

Changed in mdadm (Ubuntu):
status: Fix Committed → Fix Released
Changed in mdadm (Debian):
status: New → Fix Released
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