[Bug 2141741] Re: 55-initrd.install silently exits 0 when initrd missing causing undetectable kernel panic on NVMe systems

** Tags added: kernel-daily-bug

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https://bugs.launchpad.net/bugs/2141741

Title:
55-initrd.install silently exits 0 when initrd missing causing
undetectable kernel panic on NVMe systems

Status in linux package in Ubuntu:
Confirmed
Status in systemd package in Ubuntu:
Incomplete

Bug description:
ENVIRONMENT:
- Ubuntu 24.04 Noble (HWE kernel)
- systemd version: 255 (255.4-1ubuntu8.10)
- Kernel: 6.17.0-14-generic
- Storage: NVMe SSD
- File: /usr/lib/kernel/install.d/55-initrd.install
- Package owner: systemd (confirmed via dpkg -S)

BUG:
When initrd generation fails or is skipped during kernel
installation, 55-initrd.install detects the missing initrd
but exits 0 (success) instead of exit 1 (failure).

Relevant code in 55-initrd.install (line 26):

if [ -e "$INITRD_SRC" ]; then
ln -fs "$INITRD_SRC" "$KERNEL_INSTALL_STAGING_AREA"
else
echo "$INITRD_SRC does not exist, not installing an initrd"
fi
exit 0 ← BUG IS HERE

This silent success causes GRUB to write a boot entry for
a kernel with no initrd, with zero warning to the user.

HOW THIS CAUSES KERNEL PANIC:
Ubuntu's kernel config has CONFIG_BLK_DEV_NVME=m meaning
the NVMe storage driver exists ONLY as a module inside
initramfs. Without initramfs:
- NVMe driver never loads
- Kernel cannot see any storage device
- Results in: VFS: Unable to mount root fs on unknown-block(0,0)
- KERNEL PANIC on every boot — silent, no warning given

HOW I TRIGGERED THIS:
virtualbox-dkms 7.0.16 (dfsg) fails to build for kernel
6.17 due to missing VBox/cdefs.h header. DKMS exits code 11.
run-parts stops alphabetically — 'd' (dkms) runs before
'i' (initramfs-tools) — so initramfs is never generated.
55-initrd.install then silently exits 0 → GRUB creates
unbootable boot entry → KERNEL PANIC on reboot.

This failed silently 3 days in a row (Feb 11, 12, 13 2026)
confirmed in /var/log/dpkg.log and /var/log/apt/term.log.

PROPOSED FIX:
Change line 26 of 55-initrd.install from:
exit 0
to:
exit 1

When initrd is missing, this should be a HARD FAILURE
not a silent warning. This would cause apt to report
the error visibly and prevent GRUB from creating an
unbootable boot entry.

RELATED BUG:
https://bugs.launchpad.net/ubuntu/+source/virtualbox/+bug/2136499
(virtualbox-dkms FTBFS triggers this silent failure)

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