mpboden's questions

I've been experimenting with compiling my own kernel, and I'm having difficulty adding a local version modifier when following the instructions from BuildYourOwnKernel. This is the "Debian way" of compiling a kernel using fakefoot debian/rules binary-generic instead of compiling from mainline using make bindeb-pkg.

When following the instructions, I'm actually successful compiling the kernel. However, the +test1 suffix I added as a local version modifier is only added to the .deb archive file and not on any of the binary packages. As a result, I have a conflict during installation, because the name matches the currently installed kernel.

I'm using Ubuntu 22.04 Server.

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 22.04.4 LTS
Release:    22.04
Codename:   jammy

Current kernel:

$ uname -r
5.15.0-113-generic

Here are the steps I've followed:

1. Install dependencies

sudo apt build-dep linux linux-image-unsigned-$(uname -r)
sudo apt install fakeroot crash kexec-tools kernel-wedge libncurses5 libncurses5-dev binutils-dev

2. Download source

apt source linux-image-unsigned-$(uname -r)

3. Change into source directory

cd linux-5.15.0

4. Modify debian.master/changelog

Per the instructions:

In order to make your kernel "newer" than the stock Ubuntu kernel from which you are based, you should add a local version modifier. Add something like "+test1" to the end of the first version number in the debian.master/changelog file, before building.

Therefore, I've added +test1 to the end of the first version number as follows:

$ head -n1 debian.master/changelog
linux (5.15.0-113.123+test1) jammy; urgency=medium

5. Build kernel

fakeroot debian/rules clean
fakeroot debian/rules binary-headers binary-generic

After compiling, you'll see that the +test1 suffix has been added to all .deb files:

$ tree -L 1 /home/mike
/home/mike
├── linux-5.15.0
├── linux_5.15.0-113.123.diff.gz
├── linux_5.15.0-113.123.dsc
├── linux_5.15.0.orig.tar.gz
├── linux-buildinfo-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb
├── linux-cloud-tools-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb
├── linux-headers-5.15.0-113_5.15.0-113.123+test1_all.deb
├── linux-headers-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb
├── linux-image-unsigned-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb
├── linux-modules-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb
├── linux-modules-extra-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb
├── linux-modules-iwlwifi-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb
└── linux-tools-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb

The problem, however, is the +test1 suffix has not been added to any files within the .deb file, and as a result, there's a conflict when installing the kernel.

$ sudo dpkg -i linux-image-unsigned-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb 
dpkg: regarding linux-image-unsigned-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb containing linux-image-unsigned-5.15.0-113-generic:
 linux-image-unsigned-5.15.0-113-generic conflicts with linux-image-5.15.0-113-generic
  linux-image-5.15.0-113-generic (version 5.15.0-113.123) is present and installed.

dpkg: error processing archive linux-image-unsigned-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb (--install):
 conflicting packages - not installing linux-image-unsigned-5.15.0-113-generic
Errors were encountered while processing:
 linux-image-unsigned-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb

The headers, however, are installed:

$ sudo dpkg -i linux-headers-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb 
(Reading database ... 138403 files and directories currently installed.)
Preparing to unpack linux-headers-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb ...
Unpacking linux-headers-5.15.0-113-generic (5.15.0-113.123+test1) over (5.15.0-113.123+test1) ...
Setting up linux-headers-5.15.0-113-generic (5.15.0-113.123+test1) ...
/etc/kernel/header_postinst.d/dkms:
 * dkms: running auto installation service for kernel 5.15.0-113-generic
   ...done.

But take notice that no directory includes the local version suffix +test. It appears that it simply overwrites the existing headers.

$ tree -L 1 /usr/src
/usr/src
├── linux-headers-5.15.0-113-generic
└── python3.10

Here is a snip of the contents of linux-headers-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb:

$ dpkg -c linux-headers-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb | head -n20
drwxr-xr-x root/root         0 2024-07-07 16:31 ./
drwxr-xr-x root/root         0 2024-07-07 16:27 ./lib/
drwxr-xr-x root/root         0 2024-07-07 16:27 ./lib/modules/
drwxr-xr-x root/root         0 2024-07-07 16:27 ./lib/modules/5.15.0-113-generic/
drwxr-xr-x root/root         0 2024-07-07 16:31 ./usr/
drwxr-xr-x root/root         0 2024-07-07 16:31 ./usr/share/
drwxr-xr-x root/root         0 2024-07-07 16:31 ./usr/share/doc/
drwxr-xr-x root/root         0 2024-07-07 16:31 ./usr/share/doc/linux-headers-5.15.0-113-generic/
-rw-r--r-- root/root    714273 2024-07-07 15:58 ./usr/share/doc/linux-headers-5.15.0-113-generic/changelog.Debian.gz
-rw-r--r-- root/root      1292 2024-07-07 15:58 ./usr/share/doc/linux-headers-5.15.0-113-generic/copyright
drwxr-xr-x root/root         0 2024-07-07 16:27 ./usr/src/
drwxr-xr-x root/root         0 2024-07-07 16:27 ./usr/src/linux-headers-5.15.0-113-generic/
-rw-r--r-- root/root    261963 2024-07-07 16:27 ./usr/src/linux-headers-5.15.0-113-generic/.config
-rw-r--r-- root/root        39 2024-07-07 16:27 ./usr/src/linux-headers-5.15.0-113-generic/.gitignore
-rw-r--r-- root/root      1013 2024-07-07 16:27 ./usr/src/linux-headers-5.15.0-113-generic/.missing-syscalls.d
-rw-r--r-- root/root   1818060 2024-07-07 16:27 ./usr/src/linux-headers-5.15.0-113-generic/Module.symvers
drwxr-xr-x root/root         0 2024-07-07 16:27 ./usr/src/linux-headers-5.15.0-113-generic/arch/
drwxr-xr-x root/root         0 2024-07-07 16:27 ./usr/src/linux-headers-5.15.0-113-generic/arch/x86/
drwxr-xr-x root/root         0 2024-07-07 16:27 ./usr/src/linux-headers-5.15.0-113-generic/arch/x86/entry/
drwxr-xr-x root/root         0 2024-07-07 16:27 ./usr/src/linux-headers-5.15.0-113-generic/arch/x86/entry/syscalls/

Here is the contents of linux-image-unsigned-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb:

$ dpkg -c linux-image-unsigned-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb
drwxr-xr-x root/root         0 2024-07-07 16:29 ./
drwxr-xr-x root/root         0 2024-07-07 16:26 ./boot/
-rw------- root/root  11680480 2024-07-07 16:26 ./boot/vmlinuz-5.15.0-113-generic
drwxr-xr-x root/root         0 2024-07-07 16:29 ./usr/
drwxr-xr-x root/root         0 2024-07-07 16:27 ./usr/lib/
drwxr-xr-x root/root         0 2024-07-07 16:27 ./usr/lib/linux/
drwxr-xr-x root/root         0 2024-07-07 16:27 ./usr/lib/linux/triggers/
drwxr-xr-x root/root         0 2024-07-07 16:29 ./usr/share/
drwxr-xr-x root/root         0 2024-07-07 16:29 ./usr/share/doc/
drwxr-xr-x root/root         0 2024-07-07 16:29 ./usr/share/doc/linux-image-unsigned-5.15.0-113-generic/
-rw-r--r-- root/root    714273 2024-07-07 15:58 ./usr/share/doc/linux-image-unsigned-5.15.0-113-generic/changelog.Debian.gz
-rw-r--r-- root/root      1292 2024-07-07 15:58 ./usr/share/doc/linux-image-unsigned-5.15.0-113-generic/copyright

Here is some tail output at the end of the build process. Take note of lines that indicate building package where the package does not contain +test1 yet the .deb does.

dpkg-deb: building package 'linux-image-unsigned-5.15.0-113-generic' in '../linux-image-unsigned-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb'.
dh_installchangelogs -plinux-modules-5.15.0-113-generic
dh_installdocs -plinux-modules-5.15.0-113-generic
dh_compress -plinux-modules-5.15.0-113-generic
dh_fixperms -plinux-modules-5.15.0-113-generic -X/boot/
dh_shlibdeps -plinux-modules-5.15.0-113-generic 
dh_installdeb -plinux-modules-5.15.0-113-generic
dh_installdebconf -plinux-modules-5.15.0-113-generic
flock -w 60 /home/mike/linux-5.15.0/debian/.LOCK dh_gencontrol -plinux-modules-5.15.0-113-generic -- -Vlinux:rprovides='spl-modules,  spl-dkms,  zfs-modules,  zfs-dkms,  v4l2loopback-modules,  v4l2loopback-dkms, ' 
dpkg-gencontrol: warning: Depends field of package linux-modules-5.15.0-113-generic: substitution variable ${shlibs:Depends} used, but is not defined
dpkg-gencontrol: warning: Built-Using field of package linux-modules-5.15.0-113-generic: substitution variable ${linux:BuiltUsing} used, but is not defined
dh_md5sums -plinux-modules-5.15.0-113-generic
dh_builddeb -plinux-modules-5.15.0-113-generic
dpkg-deb: building package 'linux-modules-5.15.0-113-generic' in '../linux-modules-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb'.
if [ -f debian.master/control.d/generic.inclusion-list ] ; then \
                dh_installchangelogs -plinux-modules-extra-5.15.0-113-generic; \
dh_installdocs -plinux-modules-extra-5.15.0-113-generic; \
dh_compress -plinux-modules-extra-5.15.0-113-generic; \
dh_fixperms -plinux-modules-extra-5.15.0-113-generic -X/boot/; \
dh_shlibdeps -plinux-modules-extra-5.15.0-113-generic ; \
dh_installdeb -plinux-modules-extra-5.15.0-113-generic; \
dh_installdebconf -plinux-modules-extra-5.15.0-113-generic; \
flock -w 60 /home/mike/linux-5.15.0/debian/.LOCK dh_gencontrol -plinux-modules-extra-5.15.0-113-generic -- -Vlinux:rprovides='spl-modules,  spl-dkms,  zfs-modules,  zfs-dkms,  v4l2loopback-modules,  v4l2loopback-dkms, ' ; \
dh_md5sums -plinux-modules-extra-5.15.0-113-generic; \
dh_builddeb -plinux-modules-extra-5.15.0-113-generic; \
fi
dpkg-gencontrol: warning: Depends field of package linux-modules-extra-5.15.0-113-generic: substitution variable ${shlibs:Depends} used, but is not defined
dpkg-deb: building package 'linux-modules-extra-5.15.0-113-generic' in '../linux-modules-extra-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb'.
dh_installchangelogs -plinux-modules-iwlwifi-5.15.0-113-generic
dh_installdocs -plinux-modules-iwlwifi-5.15.0-113-generic
dh_compress -plinux-modules-iwlwifi-5.15.0-113-generic
dh_fixperms -plinux-modules-iwlwifi-5.15.0-113-generic -X/boot/
dh_shlibdeps -plinux-modules-iwlwifi-5.15.0-113-generic 
dh_installdeb -plinux-modules-iwlwifi-5.15.0-113-generic
dh_installdebconf -plinux-modules-iwlwifi-5.15.0-113-generic
flock -w 60 /home/mike/linux-5.15.0/debian/.LOCK dh_gencontrol -plinux-modules-iwlwifi-5.15.0-113-generic -- -Vlinux:rprovides='spl-modules,  spl-dkms,  zfs-modules,  zfs-dkms,  v4l2loopback-modules,  v4l2loopback-dkms, ' 
dpkg-gencontrol: warning: Built-Using field of package linux-modules-iwlwifi-5.15.0-113-generic: substitution variable ${linux:BuiltUsing} used, but is not defined
dh_md5sums -plinux-modules-iwlwifi-5.15.0-113-generic
dh_builddeb -plinux-modules-iwlwifi-5.15.0-113-generic; 
dpkg-deb: building package 'linux-modules-iwlwifi-5.15.0-113-generic' in '../linux-modules-iwlwifi-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb'.
dh_installchangelogs -plinux-buildinfo-5.15.0-113-generic
dh_installdocs -plinux-buildinfo-5.15.0-113-generic
dh_compress -plinux-buildinfo-5.15.0-113-generic
dh_fixperms -plinux-buildinfo-5.15.0-113-generic -X/boot/
dh_shlibdeps -plinux-buildinfo-5.15.0-113-generic 
dh_installdeb -plinux-buildinfo-5.15.0-113-generic
dh_installdebconf -plinux-buildinfo-5.15.0-113-generic
flock -w 60 /home/mike/linux-5.15.0/debian/.LOCK dh_gencontrol -plinux-buildinfo-5.15.0-113-generic -- -Vlinux:rprovides='spl-modules,  spl-dkms,  zfs-modules,  zfs-dkms,  v4l2loopback-modules,  v4l2loopback-dkms, ' 
dpkg-gencontrol: warning: Depends field of package linux-buildinfo-5.15.0-113-generic: substitution variable ${shlibs:Depends} used, but is not defined
dpkg-gencontrol: warning: Built-Using field of package linux-buildinfo-5.15.0-113-generic: substitution variable ${linux:BuiltUsing} used, but is not defined
dh_md5sums -plinux-buildinfo-5.15.0-113-generic
dh_builddeb -plinux-buildinfo-5.15.0-113-generic
dpkg-deb: building package 'linux-buildinfo-5.15.0-113-generic' in '../linux-buildinfo-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb'.
dh_installchangelogs -plinux-headers-5.15.0-113-generic
dh_installdocs -plinux-headers-5.15.0-113-generic
dh_compress -plinux-headers-5.15.0-113-generic
dh_fixperms -plinux-headers-5.15.0-113-generic -X/boot/
dh_shlibdeps -plinux-headers-5.15.0-113-generic 
dh_installdeb -plinux-headers-5.15.0-113-generic
dh_installdebconf -plinux-headers-5.15.0-113-generic
flock -w 60 /home/mike/linux-5.15.0/debian/.LOCK dh_gencontrol -plinux-headers-5.15.0-113-generic -- -Vlinux:rprovides='spl-modules,  spl-dkms,  zfs-modules,  zfs-dkms,  v4l2loopback-modules,  v4l2loopback-dkms, ' 
dh_md5sums -plinux-headers-5.15.0-113-generic
dh_builddeb -plinux-headers-5.15.0-113-generic
dpkg-deb: building package 'linux-headers-5.15.0-113-generic' in '../linux-headers-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb'.
dh_installchangelogs -plinux-tools-5.15.0-113-generic
dh_installdocs -plinux-tools-5.15.0-113-generic
dh_compress -plinux-tools-5.15.0-113-generic
dh_fixperms -plinux-tools-5.15.0-113-generic -X/boot/
dh_shlibdeps -plinux-tools-5.15.0-113-generic 
dh_installdeb -plinux-tools-5.15.0-113-generic
dh_installdebconf -plinux-tools-5.15.0-113-generic
flock -w 60 /home/mike/linux-5.15.0/debian/.LOCK dh_gencontrol -plinux-tools-5.15.0-113-generic -- -Vlinux:rprovides='spl-modules,  spl-dkms,  zfs-modules,  zfs-dkms,  v4l2loopback-modules,  v4l2loopback-dkms, ' 
dh_md5sums -plinux-tools-5.15.0-113-generic
dh_builddeb -plinux-tools-5.15.0-113-generic
dpkg-deb: building package 'linux-tools-5.15.0-113-generic' in '../linux-tools-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb'.
dh_installchangelogs -plinux-cloud-tools-5.15.0-113-generic
dh_installdocs -plinux-cloud-tools-5.15.0-113-generic
dh_compress -plinux-cloud-tools-5.15.0-113-generic
dh_fixperms -plinux-cloud-tools-5.15.0-113-generic -X/boot/
dh_shlibdeps -plinux-cloud-tools-5.15.0-113-generic 
dh_installdeb -plinux-cloud-tools-5.15.0-113-generic
dh_installdebconf -plinux-cloud-tools-5.15.0-113-generic
flock -w 60 /home/mike/linux-5.15.0/debian/.LOCK dh_gencontrol -plinux-cloud-tools-5.15.0-113-generic -- -Vlinux:rprovides='spl-modules,  spl-dkms,  zfs-modules,  zfs-dkms,  v4l2loopback-modules,  v4l2loopback-dkms, ' 
dh_md5sums -plinux-cloud-tools-5.15.0-113-generic
dh_builddeb -plinux-cloud-tools-5.15.0-113-generic
dpkg-deb: building package 'linux-cloud-tools-5.15.0-113-generic' in '../linux-cloud-tools-5.15.0-113-generic_5.15.0-113.123+test1_amd64.deb'.

So what's going on?

• Is this a bug?
• Is this intentional and I don't understand the process correctly?
• Or am I doing something wrong?

I'm trying to find the package that installs libnss_mdns4_minimal.so.2 using dpkg -S. The output says no path found when the file path begins with /usr/lib/ but succeeds when it begins with /lib/.

I'm using Ubuntu 22.04 Server.

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 22.04.4 LTS
Release:        22.04
Codename:       jammy

To find the location of the file, I ran the following commands:

$ sudo updatedb
$ locate mdns4_minimal
/usr/lib/x86_64-linux-gnu/libnss_mdns4_minimal.so.2

Next, I used dpkg -S to find the package that installed libnss_mdns4_minimal.so.2. The output states: no path found matching pattern.

$ dpkg -S /usr/lib/x86_64-linux-gnu/libnss_mdns4_minimal.so.2
dpkg-query: no path found matching pattern /usr/lib/x86_64-linux-gnu/libnss_mdns4_minimal.so.2

However, the following succeeds:

$ dpkg -S /lib/x86_64-linux-gnu/libnss_mdns4_minimal.so.2
libnss-mdns:amd64: /lib/x86_64-linux-gnu/libnss_mdns4_minimal.so.2

I notice that /lib is a symlink to /usr/lib:

$ ls -l /lib
lrwxrwxrwx 1 root root 7 Mar 19  2023 /lib -> usr/lib

I don't understand why no path was found when using the full path /usr/lib/x86_64-linux-gnu/libnss_mdns4_minimal.so.2, yet succeeds when using /lib/x86_64-linux-gnu/libnss_mdns4_minimal.so.2. Isn't the file the same no matter whether I'm referencing via the direct path or the via the symlink?

Can someone explain?

After every resume from screen-lock, sleep, or suspend, my laptop screen is very dim. If I type Fn+F6, then the screen jumps to 100% brightness instantly. (F5 and F6 are my brightness control keys.)

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.6 LTS
Release:    20.04
Codename:   focal

$ lspci -nnk | grep -EA3 VGA
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation Device [10de:25b8] (rev a1)
    Subsystem: Lenovo Device [17aa:22d8]
    Kernel driver in use: nouveau
    Kernel modules: nvidiafb, nouveau

$ sudo lshw -c video
  *-display                 
       description: VGA compatible controller
       product: NVIDIA Corporation
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       logical name: /dev/fb0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller bus_master cap_list rom fb
       configuration: depth=32 driver=nouveau latency=0 mode=1920x1080 visual=truecolor xres=1920 yres=1080
       resources: iomemory:400-3ff iomemory:410-40f irq:199 memory:ab000000-abffffff memory:4000000000-40ffffffff memory:4100000000-4101ffffff ioport:3000(size=128) memory:ac080000-ac0fffff

$ sudo lshw | grep -i lenovo
    product: 20YU002HUS (LENOVO_MT_20YU_BU_Think_FM_ThinkPad P17 Gen 2i)
    vendor: LENOVO
    configuration: administrator_password=disabled chassis=notebook family=ThinkPad P17 Gen 2i power-on_password=disabled sku=LENOVO_MT_20YU_BU_Think_FM_ThinkPad P17 Gen 2i uuid=4C043C28-3F2B-B211-A85C-940FFC06910B
       vendor: LENOVO
          vendor: LENOVO

Before screen-lock, sleep, or suspend:

$ cat /sys/class/backlight/nv_backlight/actual_brightness 
100

After screen-lock, sleep, or suspend:

$ cat /sys/class/backlight/nv_backlight/actual_brightness 
33

I'm entering lock mode by any of the following:

• By inactivity
• From command line with: xdg-screensaver lock
• From drop-down menu by clicking: Lock

I'm entering sleep/suspend mode by any of the following:

• From command line with: systemctl suspend
• From drop-down menu by clicking: Power Off/Log Out > Suspend

Take note that after resume from lock/sleep/suspend, the content of /sys/class/backlight/nv_backlight/actual_brightness is 33, not 100.

To achieve full brightness again, I only have to type Fn+F6 once. I find this a bit odd, because typically, if the brightness is that low, it would take several key presses. For example, to go from 30 to 100, it would normally be seven key presses.

Also, you'll notice in the Settings/Power window that the brightness level indicates it's at 100%, both before and after lock/sleep/suspend.

Finally, you'll notice that I have the setting, Dim Screen When Inactive, disabled.

In my attempt to come up with some sort of solution, I installed xbacklight with the idea that I could use it in a script to automatically reset my brightness. But this had no affect.

I also attempted the following commands, but the brightness levels don't change, and I'm unable to write to the file. Perhaps this is the wrong approach.

$ sudo chmod 644 /sys/class/backlight/nv_backlight/actual_brightness

$ sudo tee /sys/class/backlight/nv_backlight/actual_brightness <<< 100
100
tee: /sys/class/backlight/nv_backlight/actual_brightness: Input/output error

$ sudo su

# echo 100 > /sys/class/backlight/nv_backlight/actual_brightness
bash: echo: write error: Input/output error

Why is this symptom happening, and how do I fix it? Ideally, I would prefer to not incorporate a script that runs at login. This seems like treating the symptom and not the cause.

UPDATE

I attempted the two following suggested solutions, but neither worked.

Suggestion 1 - Systemd service

• Create file:

   $ cat /etc/systemd/system/nvidia-backlight-sleep
  
   [Unit]
   Description=Fix Nvidia backlight after suspend
   Before=sleep.target
   StopWhenUnneeded=yes
  
   [Service]
   Type=oneshot
   RemainAfterExit=yes
   ExecStart=/bin/bash -c "cat /sys/class/backlight/nv_backlight/actual_brightness > /run/previous_nv_backlight_brightness"
   ExecStop=/bin/bash -c "sleep 1; cat /run/previous_nv_backlight_brightness > /sys/class/backlight/nv_backlight/brightness"
  
   [Install]
   WantedBy=sleep.target
  

• Reload systemd daemons: sudo systemctl daemon-reload

• Enable service: sudo systemctl enable nvidia-backlight-sleep

Suggestion 2 - Create script in /lib/systemd/system-sleep

• Create file:

   $ cat /lib/systemd/system-sleep/nvidia-backlight-sleep
  
   #!/bin/bash
  
   case $1 in
     post)
       sleep 1
       echo 50 > /sys/class/backlight/nv_backlight/brightness
       ;;
   esac
  

• Make executable: sudo chmod 755 /lib/systemd/system-sleep/nvidia-backlight-sleep

I've been playing around with creating custom ISO images, and I've been successful. However, during the process I've come across a situation that I don't understand.

My system is Ubuntu 20.04.6 LTS Desktop.

Basically, after I run sudo unsquashfs ubuntu-server-minimal.squashfs to a directory and then list the contents of the parent directory that the resulting squashfs-root directory is in, I get the following with a number of warnings:

$ ls -l
total 2231416
dr-xr-xr-x  9 mike mike       4096 Aug  9 22:06 extracted-iso
drwxr-xr-x 18 root root       4096 Aug  9 17:20 squashfs-root
-rw-rw-r--  1 mike mike 2133391360 Sep 18 18:13 ubuntu-22.04.3-live-server-amd64.iso
-r--r--r--  1 mike mike  151560192 Sep 18 18:15 ubuntu-server-minimal.squashfs
warning: could not open directory 'iso/squashfs-root/var/lib/polkit-1/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/lib/private/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/lib/apt/lists/partial/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/lib/snapd/void/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/log/private/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/cache/private/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/cache/pollinate/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/cache/ldconfig/': Permission denied
warning: could not open directory 'iso/squashfs-root/root/': Permission denied
warning: could not open directory 'iso/squashfs-root/run/lock/lvm/': Permission denied
warning: could not open directory 'iso/squashfs-root/run/lvm/': Permission denied
warning: could not open directory 'iso/squashfs-root/etc/polkit-1/localauthority/': Permission denied
warning: could not open directory 'iso/squashfs-root/etc/ssl/private/': Permission denied

And this is where I'm confused. I know that squashfs-root is owned by root, but everyone has read access on it. Secondly, the number of warnings increase after creating various mounts necessary when chroot-ing into squashfs-root such as the following:

mount --bind /etc/resolv.conf squashfs-root/etc/resolv.conf
mount -t proc none squashfs-root/proc
mount -t sysfs none squashfs-root/sys
mount -t devpts none squashfs-root/dev/pts

Additionally, these warnings are now present with any command such as lsb_release -a and pwd:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.6 LTS
Release:    20.04
Codename:   focal
warning: could not open directory 'iso/squashfs-root/var/lib/polkit-1/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/lib/private/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/lib/apt/lists/partial/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/lib/snapd/void/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/log/private/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/cache/private/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/cache/pollinate/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/cache/ldconfig/': Permission denied
warning: could not open directory 'iso/squashfs-root/root/': Permission denied
warning: could not open directory 'iso/squashfs-root/run/lock/lvm/': Permission denied
warning: could not open directory 'iso/squashfs-root/run/lvm/': Permission denied
warning: could not open directory 'iso/squashfs-root/etc/polkit-1/localauthority/': Permission denied
warning: could not open directory 'iso/squashfs-root/etc/ssl/private/': Permission denied

$ pwd
/home/mike/custom-iso/iso
warning: could not open directory 'iso/squashfs-root/var/lib/polkit-1/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/lib/private/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/lib/apt/lists/partial/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/lib/snapd/void/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/log/private/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/cache/private/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/cache/pollinate/': Permission denied
warning: could not open directory 'iso/squashfs-root/var/cache/ldconfig/': Permission denied
warning: could not open directory 'iso/squashfs-root/root/': Permission denied
warning: could not open directory 'iso/squashfs-root/run/lock/lvm/': Permission denied
warning: could not open directory 'iso/squashfs-root/run/lvm/': Permission denied
warning: could not open directory 'iso/squashfs-root/etc/polkit-1/localauthority/': Permission denied
warning: could not open directory 'iso/squashfs-root/etc/ssl/private/': Permission denied

• If I sudo su, all warnings disappear.
• After deleting squashfs-root with sudo rm -fr squashfs-root, all warnings disappear.

So what's going on here? Why am I getting these warnings? And how can they be suppressed? Am I doing something wrong with regards to unsquashfs?

Update:

As a test, I created two VMs in VirtualBox, one with Ubuntu 20.04.6 LTS Desktop and another with 22.04.3 LTS Desktop. I downloaded the same ISO, extracted, and unsquashed the squashfs just as before to both systems. I do not get any warnings in either VM.

So it appears there's something amiss with my current system that I need help troubleshooting. Any ideas on where to start?

I'm getting an ImportError when trying to use Nala after installation:

$ sudo nala update
Traceback (most recent call last):
  File "/usr/bin/nala", line 5, in <module>
    from nala.__main__ import main
  File "/usr/lib/python3/dist-packages/nala/__main__.py", line 30, in <module>
    import nala.fetch as _fetch  # pylint: disable=unused-import
  File "/usr/lib/python3/dist-packages/nala/fetch.py", line 37, in <module>
    import typer
  File "/usr/lib/python3/dist-packages/typer/__init__.py", line 12, in <module>
    from click.termui import get_terminal_size as get_terminal_size
ImportError: cannot import name 'get_terminal_size' from 'click.termui' (/usr/lib/python3/dist-packages/click/termui.py)

This is on a server installation that has been upgraded to 22.04 and not from a fresh install of 22.04. From a historical perspective, this server was initially built with 12.04 and has been upgraded several times to 22.04.

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 22.04.2 LTS
Release:        22.04
Codename:       jammy

Nala was installed as follows:

sudo apt install nala

As a test, I installed Nala on a fresh installation of Ubuntu 22.04 in a Virtual Box machine, and it works fine. So it looks like the problem is associated with this system being an upgrade to 22.04.

I also did the following:

wget https://gitlab.com/volian/volian-archive/uploads/b20bd8237a9b20f5a82f461ed0704ad4/volian-archive-keyring_0.1.0_all.deb\
wget https://gitlab.com/volian/volian-archive/uploads/d6b3a118de5384a0be2462905f7e4301/volian-archive-nala_0.1.0_all.deb
sudo apt install ./volian-archive*.deb
sudo apt --purge autoremove nala
sudo apt install nala

Additional info:

• Nala Version:

  $ apt policy nala
  nala:
    Installed: 0.12.3
    Candidate: 0.12.3
    Version table:
   *** 0.12.3 100
          100 https://deb.volian.org/volian scar/main amd64 Packages
          100 https://deb.volian.org/volian scar/main i386 Packages
          100 /var/lib/dpkg/status
       0.12.2 100
          100 https://deb.volian.org/volian scar/main amd64 Packages
          100 https://deb.volian.org/volian scar/main i386 Packages
       0.11.1~bpo22.04.1 100
          100 http://us.archive.ubuntu.com/ubuntu jammy-backports/universe amd64 Packages
          100 http://us.archive.ubuntu.com/ubuntu jammy-backports/universe i386 Packages
  

• python3-pip version:

  $ apt policy python3-pip
  python3-pip:
    Installed: 22.0.2+dfsg-1ubuntu0.2
    Candidate: 22.0.2+dfsg-1ubuntu0.2
    Version table:
   *** 22.0.2+dfsg-1ubuntu0.2 500
          500 http://us.archive.ubuntu.com/ubuntu jammy-updates/universe amd64 Packages
          500 http://us.archive.ubuntu.com/ubuntu jammy-updates/universe i386 Packages
          500 http://security.ubuntu.com/ubuntu jammy-security/universe amd64 Packages
          500 http://security.ubuntu.com/ubuntu jammy-security/universe i386 Packages
          100 /var/lib/dpkg/status
       22.0.2+dfsg-1 500
          500 http://us.archive.ubuntu.com/ubuntu jammy/universe amd64 Packages
          500 http://us.archive.ubuntu.com/ubuntu jammy/universe i386 Packages
  

• python3-typer version:

  $ apt policy python3-typer
  python3-typer:
    Installed: 0.4.0-1
    Candidate: 0.4.0-1
    Version table:
       0.7.0-1 100
          100 https://deb.volian.org/volian scar/main amd64 Packages
          100 https://deb.volian.org/volian scar/main i386 Packages
   *** 0.4.0-1 500
          500 http://us.archive.ubuntu.com/ubuntu jammy/universe amd64 Packages
          500 http://us.archive.ubuntu.com/ubuntu jammy/universe i386 Packages
          100 /var/lib/dpkg/status
  

• python3-click version:

  $ apt policy python3-click
  python3-click:
    Installed: 8.1.3-2
    Candidate: 8.1.3-2
    Version table:
   *** 8.1.3-2 100
          100 https://deb.volian.org/volian scar/main amd64 Packages
          100 https://deb.volian.org/volian scar/main i386 Packages
          100 /var/lib/dpkg/status
       8.0.3-1 500
          500 http://us.archive.ubuntu.com/ubuntu jammy/main amd64 Packages
          500 http://us.archive.ubuntu.com/ubuntu jammy/main i386 Packages
  

• And the following resulted in no output:

  $ sudo apt-mark showhold
  

I don't know how to resolve this. Does anyone have any suggestions?