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

@Nick: Got it. Thanks for the clarification and for moving this to the
kernel team.

You're right that fixing the kernel package's handling of postinst.d
failures is the more complete solution.

I'll follow the bug and provide any testing the kernel team needs.

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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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