[Pkg-libvirt-maintainers] Bug#1137464: virt-install fails with utf-8 ValueError invalid start byte
Ari
debianbugs at semioptimal.net
Sun May 24 06:56:52 BST 2026
Package: virt-install
Version: 1:5.1.0-1
Severity: grave
Justification: renders package unusable
Dear Maintainer,
virt-install fails with
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xfc in position 10:
invalid start byte
/usr/bin/virt-install --name debug-virt-installer --disk size=20 --cdrom
~/Downloads/debian-13.5.0-amd64-netinst.iso
pretty early on: I guess when it builds a configuration for the VM it is
supposed to create
I did some debugging:
- existing disk image fails in the same way (--import)
- (not) specifying osinfo doesn't change anything
- checked all files it opens (strace --trace file -f) whether byte 10 is 0xfc:
none do.
- the storage pool locations all have ascii paths
- ran with pdb: with pdb, but without debug, the first UnicodeDecodeError
either doesn't occur or is caught.
- ran with LANG=C
I guess this is in either my setup or debian, because I couldn't find bug
report on the internet
--debug output:
$ /usr/bin/virt-install --name debug-virt-installer --disk size=7 --cdrom
~/Downloads/debian-13.5.0-amd64-netinst.iso --debug --osinfo debian13
[Sun, 24 May 2026 07:45:20 virt-install 92365] DEBUG (cli:209) Version 5.1.0
launched with command line: /usr/bin/virt-install --name debug-virt-installer
--disk size=7 --cdrom /home/arian/Downloads/debian-13.5.0-amd64-netinst.iso
--debug --osinfo debian13
[Sun, 24 May 2026 07:45:20 virt-install 92365] DEBUG (virtinstall:216)
Distilled --network options: ['default']
[Sun, 24 May 2026 07:45:20 virt-install 92365] DEBUG (virtinstall:148)
Distilled --disk options: ['size=7']
[Sun, 24 May 2026 07:45:20 virt-install 92365] DEBUG (cli:222) Requesting
libvirt URI default
[Sun, 24 May 2026 07:45:20 virt-install 92365] DEBUG (connection:129) libvirt
URI versions library=12.2.0 driver=12.2.0 hypervisor=10.2.2
[Sun, 24 May 2026 07:45:20 virt-install 92365] DEBUG (connection:110) Fetched
capabilities for qemu:///session: <capabilities>
[ ... capabilities XML redacted ]
[Sun, 24 May 2026 07:45:20 virt-install 92365] DEBUG (cli:225) Received libvirt
URI qemu:///session
[Sun, 24 May 2026 07:45:20 virt-install 92365] DEBUG (installertreemedia:57)
Error validating install location
Traceback (most recent call last):
File "/usr/share/virt-manager/virtinst/install/installertreemedia.py", line
53, in validate_path
dev.set_source_path(path)
~~~~~~~~~~~~~~~~~~~^^^^^^
File "/usr/share/virt-manager/virtinst/devices/disk.py", line 705, in
set_source_path
(newpath, vol_object, parent_pool) = diskbackend.manage_path(self.conn,
newpath)
~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
File "/usr/share/virt-manager/virtinst/diskbackend.py", line 147, in
manage_path
if not path_is_url(path) and not path_is_network_vol(conn, path):
~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
File "/usr/share/virt-manager/virtinst/diskbackend.py", line 183, in
path_is_network_vol
for volxml in conn.fetch_all_vols():
~~~~~~~~~~~~~~~~~~~^^
File "/usr/share/virt-manager/virtinst/connection.py", line 312, in
fetch_all_vols
return self._fetch_helper(
~~~~~~~~~~~~~~~~~~^
self._FETCH_KEY_VOLS, self._fetch_all_vols_raw, self.cb_fetch_all_vols
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "/usr/share/virt-manager/virtinst/connection.py", line 204, in
_fetch_helper
self._fetch_cache[key] = raw_cb()
~~~~~~^^
File "/usr/share/virt-manager/virtinst/connection.py", line 264, in
_fetch_all_vols_raw
ret.extend(self._fetch_vols_raw(poolxmlobj))
~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
File "/usr/share/virt-manager/virtinst/connection.py", line 251, in
_fetch_vols_raw
dummy1, dummy2, vols = pollhelpers.fetch_volumes(self, pool, {}, lambda
obj, ignore: obj)
~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/share/virt-manager/virtinst/pollhelpers.py", line 58, in
fetch_volumes
return _new_poll_helper(origmap, typename, list_cb, build_cb, support_cb)
File "/usr/share/virt-manager/virtinst/pollhelpers.py", line 26, in
_new_poll_helper
name = obj.name()
File "/usr/lib/python3/dist-packages/libvirt.py", line 4308, in name
ret = libvirtmod.virStorageVolGetName(self._o)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xfc in position 10:
invalid start byte
[Sun, 24 May 2026 07:45:20 virt-install 92365] DEBUG (cli:262) File
"/usr/bin/virt-install", line 7, in <module>
virtinstall.runcli()
File "/usr/share/virt-manager/virtinst/virtinstall.py", line 1315, in runcli
fail(main_e)
File "/usr/share/virt-manager/virtinst/cli.py", line 262, in fail
log.debug("".join(traceback.format_stack()))
[Sun, 24 May 2026 07:45:20 virt-install 92365] ERROR (cli:263) Validating
install media '/home/arian/Downloads/debian-13.5.0-amd64-netinst.iso' failed:
'utf-8' codec can't decode byte 0xfc in position 10: invalid start byte
[Sun, 24 May 2026 07:45:20 virt-install 92365] DEBUG (cli:265)
Traceback (most recent call last):
File "/usr/share/virt-manager/virtinst/virtinstall.py", line 1308, in runcli
sys.exit(main())
~~~~^^
File "/usr/share/virt-manager/virtinst/virtinstall.py", line 1295, in main
guest, installer = build_guest_instance(conn, options)
~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
File "/usr/share/virt-manager/virtinst/virtinstall.py", line 677, in
build_guest_instance
installer = build_installer(options, guest, installdata)
File "/usr/share/virt-manager/virtinst/virtinstall.py", line 452, in
build_installer
installer = virtinst.Installer(
guest.conn,
...<9 lines>...
is_reinstall=is_reinstall,
)
File "/usr/share/virt-manager/virtinst/install/installer.py", line 88, in
__init__
cdrom = InstallerTreeMedia.validate_path(self.conn, cdrom)
File "/usr/share/virt-manager/virtinst/install/installertreemedia.py", line
70, in validate_path
raise ValueError(msg) from None
ValueError: Validating install media
'/home/arian/Downloads/debian-13.5.0-amd64-netinst.iso' failed: 'utf-8' codec
can't decode byte 0xfc in position 10: invalid start byte
-- System Information:
Debian Release: forky/sid
APT prefers testing
APT policy: (500, 'testing'), (500, 'stable'), (400, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Kernel: Linux 7.1-amd64 (SMP w/16 CPU threads; PREEMPT)
Kernel taint flags: TAINT_CPU_OUT_OF_SPEC, TAINT_WARN
Locale: LANG=en_DK.UTF-8, LC_CTYPE=en_DK.UTF-8 (charmap=UTF-8), LANGUAGE=en_IE:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages virt-install depends on:
ii e2fsprogs 1.47.4-1
ii gir1.2-libosinfo-1.0 1.12.0-3+b2
ii python3 3.13.9-3+b1
ii python3-gi 3.56.2-1
ii python3-libvirt 12.2.0-1
ii python3-libxml2 2.15.2+dfsg-0.1
ii python3-requests 2.32.5+dfsg-1
ii xorriso 1.5.6-1.2+b2
Versions of packages virt-install recommends:
ii libvirt-clients 12.2.0-1
ii qemu-utils 1:10.2.2+ds-1
Versions of packages virt-install suggests:
pn python3-argcomplete <none>
ii virt-viewer 11.0-4
Versions of packages virt-install is related to:
ii libvirt-clients 12.2.0-1
ii libvirt-daemon 12.2.0-1
ii libvirt0 12.2.0-1
ii osinfo-db 0.20250606-1
-- no debconf information
More information about the Pkg-libvirt-maintainers
mailing list