[zfs-root] "device-mapper: reload ioctl on osprober-linux-sdaX failed: Device or resource busy" against devices owned by ZFS

[Tom Reynolds]

On a 19.10 (pre-release, 20191016 daily) zfs installation, running 'os-prober' (as 'update-grub' does by default) triggers the following error message:

x@x:~$ sudo os-prober; echo $?
device-mapper: reload ioctl on osprober-linux-sda5 failed: Device or resource busy
Command failed.
0
x@x:~$

The exit code is 0, so update-grub does not fail as a result.

Partitions on the only available storage (automatically setup by installer):

x@x:~$ sudo fdisk /dev/sda -l
Disk /dev/sda: 10 GiB, 10737418240 bytes, 20971520 sectors
Disk model: VBOX HARDDISK
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: AB7BECFB-5946-48B2-9C59-D2B1261E29A5

Device Start End Sectors Size Type
/dev/sda1 2048 1050623 1048576 512M EFI System
/dev/sda2 1050624 1153023 102400 50M Linux filesystem
/dev/sda3 1153024 2070527 917504 448M Linux swap
/dev/sda4 2070528 6264831 4194304 2G Solaris boot
/dev/sda5 6264832 20971486 14706655 7G Solaris root
x@x:~$

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: os-prober 1.74ubuntu2
ProcVersionSignature: Ubuntu 5.3.0-18.19-generic 5.3.1
Uname: Linux 5.3.0-18-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu8
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Thu Oct 17 14:19:59 2019
InstallationDate: Installed on 2019-10-17 (0 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191016.5)
SourcePackage: os-prober
UpgradeStatus: No upgrade log present (probably fresh install)

[Tom Reynolds (tomreyn)]

Related logs from journalctl -b:
os-prober[6348]: debug: running /usr/lib/os-probes/10zvol-test on /dev/sda5
os-prober[6351]: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sda5
50mounted-tests[6361]: debug: creating device mapper device /dev/mapper/osprober-linux-sda5
kernel: device-mapper: table: 253:0: linear: Device lookup failed
kernel: device-mapper: ioctl: error adding target to table

Running "sudo sh -x /usr/lib/os-probes/50mounted-tests /dev/sda5" shows that it fails with:

+ logger -t 50mounted-tests debug: creating device mapper device /dev/mapper/osprober-linux-sda5
+ dmsetup create -r osprober-linux-sda5
+ echo 0 14706655 linear /dev/sda5 0
device-mapper: reload ioctl on osprober-linux-sda5 failed: Device or resource busy
Command failed.
+ dm_device=
+ [ ]
+ do_unmount
+ [ ]
+ [ -e ]
+ rmdir /var/lib/os-prober/mount
+ exit 1

"sudo dmsetup ls" / status / info report that "No devices found".

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[emk2203 (emk2203)]

In my setup, I have 2 partitions after the Ubuntu partition (sda5). While update-grub runs through, the os-prober seems to abort and never finds the following Windows 10 partition.

[emk2203 (emk2203)]

A try with
    GRUB_OS_PROBER_SKIP_LIST="16144709171658112187@/dev/sda5"
in /etc/default/grub fails to work around the issue. The error remains.

[fermulator (fermulator)]

Please also see https://github.com/zfsonlinux/zfs/issues/9801 - it has a full set of technical details related to this topic.

[Compiler (pranav.bhattarai)]

I just installed Ubuntu 19.10 and update & upgraded everything.

And this error is what causing a weird issue while booting.

Laptop boots like, Pruple Screen > Dell logo > Purple > actually starts booting.

[Compiler (pranav.bhattarai)]

A proof: https://imgur.com/gallery/uRZFX5p

[Brian Willoughby (brian-willoughby)]

Just ran into this error today.
Recently upgraded to 19.10 and decided to try the ZFS instead of mdadm mirroring.
All was going well; until I tried to install cifs-utils for a Samba link to my office --> error (exact as in title).
This worked fine on my previous 18.04 load.
The link in #7 says a fix would 'be nice to have'; but not being able to load cifs for xfreerdp is a big problem for me.
Have not yet found any work-around.
suggestions?

[Brian Willoughby (brian-willoughby)]

Just to let you know, this error is now preventing me from updating to the 20.04 release (forced).
I have twin 500GB drives as ZFS boot device. The upgrade/install of 20.04 shows this error several times and ultimately fails.
Do I have to wait for 20.04.01 in July?

[Richard Laager (rlaager)]

brian-willoughby (and pranav.bhattarai):

The original report text confirms that "The exit code is 0, so update-grub does not fail as a result." That matches my understanding (as someone who has done a lot of ZFS installs maintaining the upstream Root-on-ZFS HOWTO) that this is purely cosmetic.

If you're not actually running other operating systems, you can simply remove the os-prober package to make the errors go away.

I'm not saying it shouldn't be fixed. But it's not actually breaking your systems, right?

[fermulator (fermulator)]

Agree w/ @rlaager, this SHOULD NOT be functionally impacting in any way. The update-grub command is not actually failing, just spewing errors during os-prober. We want to clean it up (it is cosmetic).

[Robert Chilewski (chilewskirbuu)]

device-mapper: reload ioctl on osprober-linux-sda7 failed: Device or resource busy
Command failed.
done

apt purge os-prober worked for me not getting any errors when updating grub now thanks

one more thing knocked of the list YAY!

[fermulator (fermulator)]

@chilewskirbuu that is a reasonable workaround - NOTE: it would break dual-boot though, so WARNING: don't use that as a workaround unless you are sure you are not using dual boot;

[Robert Chilewski (chilewskirbuu)]

@fermulator Thanks will keep that in Mind But I am doing Single Boot only.

[Gijs Vermariën (gijs-vermarien)]

@fermulator at the moment this is bug breaks dualboot anyway, since it will not probe my Windows os before failing and stopping. So I have to resort to using f12 to select the disk. I suppose it will be worse for people with dual boot on one drive, but they will not be able to install ZoL as easily via the installer.

[Brendan Dolan-Gavitt (brendandg)]

Is there any workaround that allows os-prober to find the Windows partitions? Or, failing that, a way to just run the part of os-prober that prints out the appropriate grub config section (I know what the partition is so if there's a way to just run something like "os-prober-windows /dev/sdb1" that would be perfect).