I can reproduce, and I've attached the full console log (!quiet, +debug). Here's some interesting pieces of the log:
EFI stub: Booting Linux Kernel... EFI stub: Generating empty DTB error: couldn't send network packet. EFI stub: Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path EFI stub: Exiting boot services... [ 0.000000] Booting Linux on physical CPU 0x0000120000 [0x413fd0c1] [ 0.000000] Linux version 5.15.0-25-generic (buildd@bos02-arm64-058) (gcc (Ubuntu 11.2.0-19ubuntu1) 11.2.0, GNU ld (GNU Binutils for Ubuntu) 2.38) #25-Ubuntu SMP Wed Mar 30 15:57:31 UTC 2022 (Ubuntu 5.15.0-25.25-generic 5.15.30) [...] [ 15.338070] Trying to unpack rootfs image as initramfs... [ 15.439137] Initramfs unpacking failed: invalid magic at start of compressed archive [ 15.461425] Freeing initrd memory: 103244K [...] We can see at the end there that the initrd failed to unpack, and that will definitely lead to a "Unable to mount root fs" panic. But why did it fail to unpack? One possibility is that the initrd failed to download. The TFTP server does report that it downloaded: Apr 8 19:38:59 avoton02 in.tftpd[4218]: RRQ from 10.229.58.47 filename /casper/vmlinuz Apr 8 19:39:02 avoton02 in.tftpd[4220]: RRQ from 10.229.58.47 filename /casper/vmlinuz Apr 8 19:39:06 avoton02 in.tftpd[4221]: RRQ from 10.229.58.47 filename /casper/initrd OK, then maybe it only partially downloaded? Well, the amount of memory the kernel reports freeing is close to the size of the initrd, so that's probably not it: $ du -s /srv/tftp/casper/initrd 103248 /srv/tftp/casper/initrd Then perhaps the kernel doesn't support decompressing this compression format. What is the compression format? $ file /srv/tftp/casper/initrd /srv/tftp/casper/initrd: Zstandard compressed data (v0.8+), Dictionary ID: None Does the kernel support that? Let's look at the kernel config: ubuntu@avoton02:/tmp$ dpkg-deb -x linux-modules-5.15.0-25-generic_5.15.0-25.25_arm64.deb x ubuntu@avoton02:/tmp$ grep ZSTD_DECOMPRESS x/boot/config-5.15.0-25-generic CONFIG_ZSTD_DECOMPRESS=y hm.. it does. That's weird. The other mystery is that this all seems to work when booted from the ISO. Let's take a look at that boot log and see if we can spot anything different. ** Attachment added: "howzit-pxe-console.log" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1967562/+attachment/5578333/+files/howzit-pxe-console.log ** Changed in: subiquity (Ubuntu) Status: Incomplete => Invalid ** Changed in: linux (Ubuntu) Assignee: (unassigned) => dann frazier (dannf) -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1967562 Title: jammy beta (220330) arm iso pxe boot kernel panic on Ampere Mt. Jade Status in linux package in Ubuntu: Incomplete Status in subiquity package in Ubuntu: Invalid Bug description: = Description = Platforms: Ampere Mt. Jade Altra (bizzy), Cavium thunderX crb2s (recht) Image: Jammy Beta (220330) I setup my pxe server to provision jammy beta and got the following kernel panic message after grub stage: log from console log [ 1.176614] integrity: Couldn't parse dbx signatures: -74^M [ 1.371630] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)^M [ 1.379891] CPU: 42 PID: 1 Comm: swapper/0 Not tainted 5.15.0-23-generic #23-Ubuntu^M [ 1.387535] Hardware name: WIWYNN Mt.Jade Server System B81.030Z1.0007/Mt.Jade Motherboard, BIOS 1.6.20210526 (SCP: 1.06.20210526) 2021/05/26^M [ 1.400215] Call trace:^M [ 1.402649] dump_backtrace+0x0/0x1ec^M [ 1.406310] show_stack+0x24/0x30^M [ 1.409614] dump_stack_lvl+0x68/0x84^M [ 1.413271] dump_stack+0x18/0x34^M [ 1.416573] panic+0x18c/0x39c^M [ 1.419616] mount_block_root+0x160/0x210^M [ 1.423622] mount_root+0x12c/0x14c^M [ 1.427097] prepare_namespace+0x140/0x1a0^M [ 1.431182] kernel_init_freeable+0x1c8/0x214^M [ 1.435527] kernel_init+0x30/0x160^M [ 1.439006] ret_from_fork+0x10/0x20^M [ 1.442573] SMP: stopping secondary CPUs^M [ 1.447323] Kernel Offset: 0x55263ee90000 from 0xffff800008000000^M [ 1.453404] PHYS_OFFSET: 0x80000000^M [ 1.456879] CPU features: 0x000085c1,a3302e42^M [ 1.461225] Memory Limit: none^M [ 1.464271] ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) ]---^M = Steps to Reproduce = 1. Followed this guide to setup the pxe server https://discourse.ubuntu.com/t/netbooting-the-live-server-installer-via-uefi-pxe-on-arm-aarch64-arm64-and-x86-64-amd64/19240 with the jammy beta image (220330) http://cdimage.ubuntu.com/ubuntu-server/daily-live/20220330/jammy-live-server-arm64.iso 1-1. You may use this script to perform the set-up https://github.com/tai271828/ubuntu-autoinstall-pxe-server by invoking: `sudo ./setup-pxe-server.sh --url http://cdimage.ubuntu.com/ubuntu-server/daily-live/20220330/jammy-live-server-arm64.iso` 2. Boot the system via PXE 3. Select Ubuntu at Grub menu = Expected Result = The image is loaded to the system locally via PXE, and subiquity is launched = Actual Result = Console log simply shows nothing for 10 seconds and then the kernel panic shows up. = Additional Information = - If we install via the virtual CD of the server, subiquity could be launched and the installation process completes successfully. - MAAS could deploy Jammy to the Mt. 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