Comment 22 for bug 1864992

I do not believe this is a duplicate; It is more likely a *packaging* issue. The question remains for this bug, why does it only appear in the focal kernels; but not Eoan or older?

And if someone could confirm whether or not the linux-generic or linux-modules generate this file and when (unpack, deb postinst, kernel install hook?)

Another reason why this isn't a duplicate as the error message is unrelated to the contents of the initrd, but rather when depmod -a -S is called (postins of linux-modules package).

On Eoan we can remove the file in question and regenerate the file with:

depmod -a -F /boot/System.map-5.3.0-40-generic;

this command does not produce the error message on any release expect Focal.

# eoan

root@rharper-e1:~# cat /etc/issue
Ubuntu 19.10 \n \l

root@rharper-e1:~# dpkg --list | grep linux-
ii linux-base 4.5ubuntu2 all Linux image base package
ii linux-firmware 1.183.4 all Firmware for Linux kernel drivers
ii linux-generic 5.3.0.40.34 amd64 Complete Generic Linux kernel and headers
ii linux-headers-5.3.0-40 5.3.0-40.32 all Header files related to Linux kernel version 5.3.0
ii linux-headers-5.3.0-40-generic 5.3.0-40.32 amd64 Linux kernel headers for version 5.3.0 on 64 bit x86 SMP
ii linux-headers-generic 5.3.0.40.34 amd64 Generic Linux kernel headers
ii linux-image-5.3.0-40-generic 5.3.0-40.32 amd64 Signed kernel image generic
ii linux-image-generic 5.3.0.40.34 amd64 Generic Linux kernel image
ii linux-modules-5.3.0-40-generic 5.3.0-40.32 amd64 Linux kernel extra modules for version 5.3.0 on 64 bit x86 SMP
ii linux-modules-extra-5.3.0-40-generic 5.3.0-40.32 amd64 Linux kernel extra modules for version 5.3.0 on 64 bit x86 SMP

root@rharper-e1:~# rm /lib/modules/5.3.0-40-generic/modules.builtin.bin
root@rharper-e1:~# depmod -a -F /boot/System.map-5.3.0-40-generic 5.3.0-40-generic
root@rharper-e1:~# ls -al /lib/modules/5.3.0-40-generic/modules.builtin.bin
-rw-r--r-- 1 root root 9943 Mar 2 15:03 /lib/modules/5.3.0-40-generic/modules.builtin.bin

# On focal this errors:
root@rharper-f1:~# cat /etc/issue
Ubuntu Focal Fossa (development branch) \n \l

root@rharper-f1:~# dpkg --list | grep linux-
ii linux-5.4-headers-5.4.0-14 5.4.0-14.17 all Header files related to Linux kernel version 5.4.0
ii linux-base 4.5ubuntu2 all Linux image base package
ii linux-firmware 1.186 all Firmware for Linux kernel drivers
ii linux-generic 5.4.0.14.17 amd64 Complete Generic Linux kernel and headers
ii linux-headers-5.4.0-14-generic 5.4.0-14.17 amd64 Linux kernel headers for version 5.4.0 on 64 bit x86 SMP
ii linux-headers-generic 5.4.0.14.17 amd64 Generic Linux kernel headers
ii linux-image-5.4.0-14-generic 5.4.0-14.17 amd64 Signed kernel image generic
ii linux-image-generic 5.4.0.14.17 amd64 Generic Linux kernel image
ii linux-modules-5.4.0-14-generic 5.4.0-14.17 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
ii linux-modules-extra-5.4.0-14-generic 5.4.0-14.17 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
root@rharper-f1:~# ls -al /lib/modules/5.4.0-14-generic/modules.builtin.bin
-rw-r--r-- 1 root root 10257 Mar 2 15:01 /lib/modules/5.4.0-14-generic/modules.builtin.bin
root@rharper-f1:~# set -o vi
root@rharper-f1:~# rm /lib/modules/5.4.0-14-generic/modules.builtin.bin
root@rharper-f1:~# depmod -a -F /boot/System.map-5.4.0-14-generic 5.4.0-14-generic
depmod: ERROR: ../libkmod/libkmod.c:515 lookup_builtin_file() could not open builtin file '/lib/modules/5.4.0-14-generic/modules.builtin.bin'
depmod: ERROR: ../libkmod/libkmod.c:515 lookup_builtin_file() could not open builtin file '/lib/modules/5.4.0-14-generic/modules.builtin.bin'
depmod: ERROR: ../libkmod/libkmod.c:515 lookup_builtin_file() could not open builtin file '/lib/modules/5.4.0-14-generic/modules.builtin.bin'
depmod: ERROR: ../libkmod/libkmod.c:515 lookup_builtin_file() could not open builtin file '/lib/modules/5.4.0-14-generic/modules.builtin.bin'