Verification done on lunar-proposed.
$ lxc launch ubuntu:lunar lunar-loop --vm $ lxc shell lunar-loop
# apt install -y gcc # gcc -o test-loop test-loop.c
# add-apt-repository -y -p proposed # apt-cache madison linux-image-6.2.0-30-generic linux-image-6.2.0-30-generic | 6.2.0-30.30 | http://archive.ubuntu.com/ubuntu lunar-proposed/main amd64 Packages linux-image-6.2.0-30-generic | 6.2.0-30.30 | http://security.ubuntu.com/ubuntu lunar-proposed/main amd64 Packages # apt install -y linux-image-6.2.0-30-generic
# echo "GRUB_DEFAULT='Advanced options for Ubuntu>Ubuntu, with Linux 6.2.0-30-generic'" >/etc/default/grub.d/99-default.cfg # update-grub # reboot
# uname -rv 6.2.0-30-generic #30-Ubuntu SMP PREEMPT_DYNAMIC Wed Aug 9 13:33:35 UTC 2023
...
default: works (fixed)
# cat /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-6.2.0-30-generic root=PARTUUID=a335a269-dd48-4d3a-907a-2d2a2c6d53d7 ro console=tty1 console=ttyS0 panic=-1
# ./test-loop #
max_loop=0: works (expected)
# echo 'GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT max_loop=0"' >/etc/default/grub.d/99-maxloop.cfg # update-grub && reboot
# cat /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-6.2.0-30-generic root=PARTUUID=a335a269-dd48-4d3a-907a-2d2a2c6d53d7 ro console=tty1 console=ttyS0 max_loop=0 panic=-1
max_loop=8: fails (expected)
# echo 'GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT max_loop=8"' >/etc/default/grub.d/99-maxloop.cfg # update-grub && reboot
# cat /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-6.2.0-30-generic root=PARTUUID=a335a269-dd48-4d3a-907a-2d2a2c6d53d7 ro console=tty1 console=ttyS0 max_loop=8 panic=-1
# ./test-loop open: /dev/loop8: No such device or address
Verification done on lunar-proposed.
$ lxc launch ubuntu:lunar lunar-loop --vm
$ lxc shell lunar-loop
# apt install -y gcc
# gcc -o test-loop test-loop.c
# add-apt-repository -y -p proposed 6.2.0-30- generic 6.2.0-30- generic | 6.2.0-30.30 | http:// archive. ubuntu. com/ubuntu lunar-proposed/main amd64 Packages 6.2.0-30- generic | 6.2.0-30.30 | http:// security. ubuntu. com/ubuntu lunar-proposed/main amd64 Packages 6.2.0-30- generic
# apt-cache madison linux-image-
linux-image-
linux-image-
# apt install -y linux-image-
# echo "GRUB_DEFAULT= 'Advanced options for Ubuntu>Ubuntu, with Linux 6.2.0-30-generic'" >/etc/default/ grub.d/ 99-default. cfg
# update-grub
# reboot
# uname -rv
6.2.0-30-generic #30-Ubuntu SMP PREEMPT_DYNAMIC Wed Aug 9 13:33:35 UTC 2023
...
default: works (fixed)
# cat /proc/cmdline /boot/vmlinuz- 6.2.0-30- generic root=PARTUUID= a335a269- dd48-4d3a- 907a-2d2a2c6d53 d7 ro console=tty1 console=ttyS0 panic=-1
BOOT_IMAGE=
# ./test-loop
#
max_loop=0: works (expected)
# echo 'GRUB_CMDLINE_ LINUX_DEFAULT= "$GRUB_ CMDLINE_ LINUX_DEFAULT max_loop=0"' >/etc/default/ grub.d/ 99-maxloop. cfg
# update-grub && reboot
# cat /proc/cmdline /boot/vmlinuz- 6.2.0-30- generic root=PARTUUID= a335a269- dd48-4d3a- 907a-2d2a2c6d53 d7 ro console=tty1 console=ttyS0 max_loop=0 panic=-1
BOOT_IMAGE=
# ./test-loop
#
max_loop=8: fails (expected)
# echo 'GRUB_CMDLINE_ LINUX_DEFAULT= "$GRUB_ CMDLINE_ LINUX_DEFAULT max_loop=8"' >/etc/default/ grub.d/ 99-maxloop. cfg
# update-grub && reboot
# cat /proc/cmdline /boot/vmlinuz- 6.2.0-30- generic root=PARTUUID= a335a269- dd48-4d3a- 907a-2d2a2c6d53 d7 ro console=tty1 console=ttyS0 max_loop=8 panic=-1
BOOT_IMAGE=
# ./test-loop
open: /dev/loop8: No such device or address