I’ve been having issues with the pc-kernel 22-hwe track images failing to boot. The boot failure occurs due to a kernel panic when opening the root device. This occurs both on an Intel NUC13anhi7 and qemu.
Here’s the qemu trace:
[ 0.651875] /dev/root: Can't open blockdev
[ 0.652808] VFS: Cannot open root device "" or unknown-block(0,0): error -6
[ 0.653749] Please append a correct "root=" boot option; here are the available partitions:
[ 0.654822] fd00 3097600 vda
[ 0.654829] driver: virtio_blk
[ 0.658604] fd01 1024 vda1 4fa06cee-60c7-4be7-a22c-d4cb8e2fff59
[ 0.658607]
[ 0.660521] fd02 1228800 vda2 ac28c6e8-afaa-489b-b256-aeb617d68a18
[ 0.660523]
[ 0.661772] List of all bdev filesystems:
[ 0.662408] ext3
[ 0.662409] ext2
[ 0.662752] ext4
[ 0.663180] squashfs
[ 0.663528] vfat
[ 0.663940] fuseblk
[ 0.664283]
[ 0.665167] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
[ 0.666625] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.8.0-44-generic #44~22.04.1-Ubuntu
[ 0.667731] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[ 0.668836] Call Trace:
[ 0.669352] <TASK>
[ 0.669817] dump_stack_lvl+0x27/0xa0
[ 0.670462] dump_stack+0x10/0x20
[ 0.671866] panic+0x366/0x3c0
[ 0.672402] mount_root_generic+0x1a5/0x350
[ 0.673165] mount_root+0x98/0x100
[ 0.673972] ? __pfx_kernel_init+0x10/0x10
[ 0.674608] prepare_namespace+0x6c/0x2f0
[ 0.675224] kernel_init_freeable+0x1c6/0x210
[ 0.676350] kernel_init+0x1b/0x200
[ 0.676923] ret_from_fork+0x44/0x70
[ 0.677474] ? __pfx_kernel_init+0x10/0x10
[ 0.678112] ret_from_fork_asm+0x1b/0x30
[ 0.678682] </TASK>
[ 0.679169] Kernel Offset: 0x2ea00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
Here’s my seed.manifest:
bare 5
core22 1621
pc 146
pc-kernel 1985
snapd 21759
Notice it is using pc-kernel 1985 which is the 22-hwe/stable revision at the time of this post.
$ snap info pc-kernel
...
22-hwe/stable: 6.8.0-44.44~22.04.1 2024-09-19 (1985) 293MB -
If use an old 22-hwe revision, 1921, the boot is successful.
$ snap download pc-kernel --revision 1921
$ ubuntu-image snap model.assert --snap pc-kernel_1921.snap
$ qemu-system-x86_64 ... pc.img
$ ssh localhost -p 8022
$ snap info pc-kernel
...
installed: 6.5.0.44.44~22.04.1 (1921) 285MB kernel
If i then run snap refresh pc-kernel and let the machine reboot, the next boot fails and kernel snap is reverted.
I can successfully change the channel to 22-oem/stable which is revision 1954 and still the 6.5 kernel series
Reproduction is simple; just create a basic image using ubuntu-image and boot using qemu from the docs
Here’s my model.json:
{
"type": "model",
"series": "16",
"authority-id": "***",
"brand-id": "***",
"system-user-authority": "*",
"model": "ubuntu-core-22-amd64",
"architecture": "amd64",
"timestamp": "2024-09-25T13:52:46+00:00",
"base": "core22",
"grade": "dangerous",
"snaps": [
{
"name": "pc",
"type": "gadget",
"default-channel": "22/stable"
},
{
"name": "pc-kernel",
"type": "kernel",
"default-channel": "22-hwe/stable"
},
{
"name": "bare",
"type": "base",
"default-channel": "latest/stable"
},
{
"name": "core22",
"type": "base",
"default-channel": "latest/stable"
},
{
"name": "snapd",
"type": "snapd",
"default-channel": "latest/stable"
}
]
}
Please advise if I should revert to the 22-oem series for the 6.5 kernel instead of the 6.8 kernel. These images have been built using the 22-hwe/stable series for the past ~2 years in order to use some networking hardware not available in the 5.15 kernel.
