[pkg-go] Bug#1008762: debos: does not work with Linux 5.13+

[Sascha Silbe]

Package: debos
Version: 1.0.0+git20201203.e939090-4+b3
Severity: important
Tags: upstream
X-Debbugs-Cc: sascha-debian-bugs-debos-2022-03-31 at silbe.org

Dear Maintainer,

debos does not work on systems running a 5.13 or newer kernel because
the 9pnet_virtio and virtio_pci modules cannot be loaded:

=== Begin debos --show-boot output ===
[    1.443424] Run /init as init process
modprobe: can't load module virtio_pci_modern_dev (kernel/drivers/virtio/virtio_pci_modern_dev.ko): No such file or directory
[    1.511627] 9pnet: Installing 9P2000 support
modprobe: can't load module netfs (kernel/fs/netfs/netfs.ko): No such file or directory
mount: mounting usr on /usr failed: No such device
mount: mounting sbin on /sbin failed: No such device
mount: mounting bin on /bin failed: No such device
mount: mounting lib on /lib failed: No such device
/init: exec: line 28: /lib/systemd/systemd: not found
[    1.534807] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00007f00
[...]
open /tmp/fakemachine-733191250/result: no such file or directory
=== End debos --show-boot output ===

Since Linux 5.13 there's a new module "netfs" that the "9p" module
depends on. Because fakemachine does not take module dependencies into
account, "netfs" is not copied into the initramfs.

This is in fact the same issue that Steve Langasek encountered in
#989145 "Please do not use uml fakemachine backend in the DEP-8 test".

The naive approach of adding "netfs" to InitrdModules would break
support for kernels older than 5.13. The real solution would be to
perform module dependency resolution but quick work-arounds would be
to either copy all modules (probably increasing early boot memory
usage by ~0.5GiB which may be acceptable) or to copy "netfs" only if
present.

Similarly, virtio_pci depends on virtio_pci_modern_dev which isn't
included in InitrdModules. The same compatibility concerns apply.


Sascha

-- System Information:
Debian Release: 11.3
  APT prefers stable-updates
  APT policy: (990, 'stable-updates'), (990, 'stable-security'), (990, 'stable'), (500, 'stable-debug'), (100, 'testing'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386, armhf, armel

Kernel: Linux 5.16.0-0.bpo.4-amd64 (SMP w/4 CPU threads; PREEMPT)
Locale: LANG=en_GB, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en:en_US:C:de_DE:de
Shell: /bin/sh linked to /bin/bash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages debos depends on:
ii  busybox            1:1.30.1-6+b3
ii  debootstrap        1.0.123
ii  libc6              2.31-13+deb11u3
ii  libglib2.0-0       2.66.8-1
ii  libostree-1-1      2020.8-2+deb11u1
ii  qemu-system-x86    1:5.2+dfsg-11+deb11u1
ii  qemu-user-static   1:5.2+dfsg-11+deb11u1
ii  systemd-container  247.3-7

Versions of packages debos recommends:
ii  bmap-tools         3.5-3
ii  bzip2              1.0.8-4
ii  e2fsprogs          1.46.2-2
ii  linux-image-amd64  5.16.12-1~bpo11+1
ii  mount              2.36.1-8+deb11u1
ii  ovmf               2020.11-2+deb11u1
ii  parted             3.4-1
ii  udev               247.3-7
ii  xz-utils           5.2.5-2
ii  zip                3.0-12

debos suggests no packages.

-- no debconf information