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

** Changed in: grub2 (Debian) Status: Unknown => New -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb 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 grub2 package in Ubuntu: Confirmed Status in linux package in Ubuntu: Confirmed Status in systemd package in Ubuntu: Invalid Status in grub2 package in Debian: New Bug description: [ Impact ] When a kernel postinst hook fails (e.g. DKMS module build failure), the kernel package remains half-configured: vmlinuz is installed and /usr/lib/linux/triggers/<version> is present, but no matching initrd is generated. A subsequent update-grub invocation (such as during removal of an older kernel) scans /boot and generates a boot menuentry for the incomplete kernel without an initrd line. On systems where storage drivers (NVMe, SATA, SAS) are built as modules, booting this entry causes an immediate, undetectable kernel panic (VFS: Unable to mount root fs on unknown-block(0,0)). [ Fix ] In /etc/grub.d/10_linux, when inspecting a kernel where no initrd was found (test -z "${initrd_real}"), check if a pending kernel trigger marker exists in /usr/lib/linux/triggers/${version} or /usr/lib/linux/triggers/${alt_version}. If the trigger marker is present, skip generating a boot menuentry for that kernel image. This prevents update-grub from publishing unbootable kernels to grub.cfg. [ Test Plan ] 1. Simulate an incomplete kernel installation: sudo touch /boot/vmlinuz-9.9.0-test-generic sudo touch /usr/lib/linux/triggers/9.9.0-test-generic sudo rm -f /boot/initrd.img-9.9.0-test-generic 2. Run sudo update-grub. 3. Verify behavior: - Without fix: GRUB outputs "Found linux image: /boot/vmlinuz-9.9.0-test-generic" and writes a stanza lacking an initrd line. - With fix: GRUB outputs "Skipping linux image with pending post-installation trigger and no initrd: /boot/vmlinuz-9.9.0-test-generic", and no stanza is generated. 4. Clean up test files (sudo rm -f /boot/vmlinuz-9.9.0-test-generic /usr/lib/linux/triggers/9.9.0-test-generic) and verify standard installed kernels generate valid boot entries. [ Where problems could occur ] The check only triggers when both conditions are met: initrd_real is empty AND a trigger marker exists in /usr/lib/linux/triggers/. Custom kernels intentionally configured without an initrd do not have markers under /usr/lib/linux/triggers/ and continue to work as before. If a kernel postinst script fails to clean up its trigger marker after a successful run, that kernel would be skipped until the stale marker is removed. [ Other Info ] - Debian BTS bug: https://bugs.debian.org/1151014 - Development series (stonking): debdiff prepared against 2.14-2ubuntu3 (version 2.14-2ubuntu4). - Stable SRU (noble): debdiff prepared against 2.12-1ubuntu7.3 (version 2.12-1ubuntu7.4). - PPA test builds: ppa:steelf/ppa (grub2 2.14-2ubuntu4~ppa1, grub2 2.12-1ubuntu7.4~ppa1). --- [ Original Report ] 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) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/2141741/+subscriptions