15716 initramfs kernelpanic switch_root 2025-01-14 10:13:24 +0000 initrdscripts ignores virtual runtime "base-utils", hard dependency on busybox 2025-04-13 16:59:38 +0000 1 1 7 Build System, Metadata & Runtime OE-Core core 5.99 Other x86_64 RESOLVED FIXED Medium+ normal 5.2 M3 1 jbk gavrosc gavrosc kexin.hao meta.mr.watcher meta.watcher randy.macleod yoann.congal --- --- Don't know oldest_to_newest 100631 0 jbk 2025-01-14 10:13:24 +0000 I recently had an issue with including an initramfs in my build, which I tracked down to the following interaction between the "finish" initrdscript and the virtual runtime for "base-utils" used in the initramfs images of oe-core. The issue: The initrdscript "finish" of the initramfs-framework is not provider-/runtime-agnostic. It requires busybox as virtual runtime for "base-utils". Changing the base-utils to "packagegroup-core-base-utils" breaks the aforementioned "finish" script, leading to a kernel panic as the initramfs cannot transition to the final userspace / final rootfs. The cause: Reason is line 44, executing the switch_root command. switch_root is either provided by busybox or by util-linux, while the latter is shipped with packagegroup-core-base-utils. (Or maybe even a custom/another implementation in rare cases). However: The invokation as in line 44 of the "finish" script needs the "-c" option , which is busybox specific and not supported by the util-linux implementation. See switch_root as implemented by util-linux: https://man.archlinux.org/man/core/util-linux/switch_root.8.en And as implemented by busybox: https://www.busybox.net/downloads/BusyBox.html Hence, when not using busybox as base-utils provider, inlcuding a initramfs based on the initrdscripts shipped with oe-core, it fails to transition to the final userspace, leading to a kernel panic. Meaning: 1. Neither core-image-initramfs-boot nor core-image-minimal-initramfs consider this behavior. Both include the base-utils as specified in the virtual runtime (${VIRTUAL-RUNTIME_base-utils}). As soon as you change the virtual runtime in your build, those images break, leading to a kernel panic upon boot. 2. You have to either use "busybox" as hard-dependency in your own initramfs or ship your own initrdscripts Version: I worked with the current master, however I see that the busybox specific switch_root was used ever since the "finish" script was included in oe-core. Same with the initramfs images shipped with oe-core, which seem to have used the virtual runtime for base-utils for quite a while, therefore breaking when not using busybox as base-utils. Reproduce as follows: - Chane your base-util provier: PREFERRED_PROVIDER_virtual/base-utils = "packagegroup-core-base-utils" VIRTUAL-RUNTIME_base-utils ?= "packagegroup-core-base-utils" - Include one of the initramfs images shipped with oe-core in your build: INITRAMFS_IMAGE = "core-image-minimal-initramfs" - Build an image of your choice, including the initramfs - Boot will lead to a kernel panic Possible resolution: - Either make the initrdscripts provider-agnostic by removing the "-c" option, or by only using the "-c" option when busybox is the switch_root implementation - Or use busybox as dependency in the initramfs images shipped with oe-core, possibly mentioning in the docs that you cannot use another virtual provider for base-utils in conjunction with the initrdscripts as shipped by oe-core. I hope I provided enough information to confirm and possibly resolve this bug. 100664 1 randy.macleod 2025-01-16 15:42:57 +0000 Kevin may have an idea about how to handle this bug but I'm just CCing him for now. Other people are welcome to submit a patch if they have one. 101379 2 gavrosc 2025-03-15 12:54:35 +0000 hi jbk, thank you for the description. It is very detailed. I tried to reproduce the issue. I set the following variables in local.conf: PREFERRED_PROVIDER_virtual/base-utils = "packagegroup-core-base-utils" VIRTUAL-RUNTIME_base-utils ?= "packagegroup-core-base-utils" INITRAMFS_IMAGE = "core-image-minimal-initramfs" INITRAMFS_MAXSIZE = "160000" execute: bitbake core-image-minimal Then i tried to use qemu( runqemu qemux86_64 ) but i couldnt reproduce it. - Are the above settings ok? if yes then probably qemu can not reproduce this behavior - Did you use another hardware? Br Christos 101441 3 randy.macleod 2025-03-20 14:59:27 +0000 JBK - ping. 101453 4 gavrosc 2025-03-21 11:49:02 +0000 hi i reproduced it using qemu. add lines in local.conf: PREFERRED_PROVIDER_virtual/base-utils = "packagegroup-core-base-utils" VIRTUAL-RUNTIME_base-utils ?= "packagegroup-core-base-utils" INITRAMFS_IMAGE = "core-image-minimal-initramfs" INITRAMFS_MAXSIZE = "160000" INITRAMFS_IMAGE_BUNDLE = "1" IMAGE_FSTYPES += "cpio.gz" Run: bitbake core-image-minimal-initramfs Run: qemu-system-x86_64 -kernel tmp/deploy/images/qemux86-64/bzImage \ -initrd tmp/deploy/images/qemux86-64/core-image-minimal-initramfs-qemux86-64.cpio.gz \ -nographic -append "console=ttyS0 rdinit=/bin/sh" The result is kernel panic. If i set busybox as provider (PREFERRED_PROVIDER_virtual/base-utils and VIRTUAL-RUNTIME_base-utils) then boot is ok. I will prepare a patch the upcoming week. Randy and Richard thank you for the support yesterday :). Br Christos 101533 5 gavrosc 2025-03-28 18:07:10 +0000 hi i think the right way to reproduce it is the following (and not in the previous comment i made): add in local.conf: PREFERRED_PROVIDER_virtual/base-utils = "packagegroup-core-base-utils" VIRTUAL-RUNTIME_base-utils ?= "packagegroup-core-base-utils" INITRAMFS_IMAGE = "core-image-minimal-initramfs" INITRAMFS_MAXSIZE = "160000" Run: bitbake core-image-minimal Run qemu manually including initramfs: sudo qemu-system-x86_64 \ -device virtio-net-pci,netdev=net0,mac=52:54:00:12:34:02 \ -netdev tap,id=net0,ifname=tap0,script=no,downscript=no \ -object rng-random,filename=/dev/urandom,id=rng0 \ -device virtio-rng-pci,rng=rng0 \ -drive file=/home/cg/poky/build/tmp/deploy/images/qemux86-64/core-image-minimal-qemux86-64.rootfs.ext4,if=virtio,format=raw \ -usb \ -device usb-tablet \ -usb \ -device usb-kbd \ -cpu IvyBridge \ -machine q35 \ -smp 4 \ -m 256 \ -serial mon:vc \ -serial null \ -device virtio-vga \ -display sdl,show-cursor=on \ -kernel /home/cg/poky/build/tmp/deploy/images/qemux86-64/bzImage \ -initrd /home/cg/poky/build/tmp/deploy/images/qemux86-64/core-image-minimal-initramfs-qemux86-64.cpio.gz \ -append 'root=/dev/vda rw ip=192.168.7.2::192.168.7.1:255.255.255.0::eth0:off:8.8.8.8 net.ifnames=0 oprofile.timer=1 tsc=reliable no_timer_check rcupdate.rcu_expedited=1 swiotlb=0' The result is that boot stops with message: "Switch_root: invalid option — ‘c’ Try ‘switch_root –help’ for more information" If i set busybox as provider (PREFERRED_PROVIDER_virtual/base-utils and VIRTUAL-RUNTIME_base-utils) then boot is ok. 101640 6 gavrosc 2025-04-13 16:59:38 +0000 The patch is merged in the master: https://git.openembedded.org/openembedded-core/commit/?id=0f745024fd40518f98390008b4f613d5641df416