Snapcraft unable to compile ARM64 kernel
Metadata
Current evaluation
ARM64 core20 kernel cross-builds fail while fetching snapd:arm64; a minimal apt reproducer exists, but the report has no maintainer triage or release mapping.
Suggested action: needs triage
Reason: The report includes exact Snapcraft versions, build commands, package configuration, and logs, and the author later reproduced the failure directly with `apt-get download snapd:arm64` on Ubuntu 20.04 and 22.04. However, the only comment is from the reporter, there are no labels or maintainer response, and the failing function no longer exists in the current tree following kernel-plugin work including #6237, so maintainers must determine which supported releases are affected or fixed.
Evaluated by: mr-cal-bot
Impact:
45
Quick Win:
14
Complexity:
62
Confidence:
87
Actionability:
82
Issue body
### Bug Description
I am trying to cross-compile a kernel for a ARM64 device, and it seems on both 7.x/stable and 8.x/stable channels that the snapcraft application fails to download the snapd:arm64 package, with the error: E: Can't select candidate version from package snapd:arm64 as it has no candidate
Failed to build 'kernel'.
This build-process happens on a Ubuntu Focal Multipass instance running on a AMD64 machine.
Snapcraft versions: 7.x/stable (7.5.8) and 8.x/stable (8.5.1)
This has worked last time I tried to compile a kernel, a few months back.
### To Reproduce
Not sure how to replicate, try to cross-compile a kernel?
Multipass instance compile options: (Manual compile commands)
`snapcraft --target-arch=arm64 --destructive-mode --enable-experimental-target-arch --enable-experimental-plugins`
### Environment
Running Multipass snap, version 1.15.0 on Ubuntu Bionic machine
Mutipass container version: Ubuntu 20.04.6 LTS
### snapcraft.yaml
```yaml
name: my-kernel
version: "20-8"
adopt-info: kernel
summary: Generic Linux kernel description: |
Kernel for testing
grade: stable
confinement: strict
type: kernel
architectures:
- build-on: amd64
run-on: arm64
build-base: core20
parts:
kernel:
plugin: kernel
source: github-link-removed
source-type: git
source-branch: lf-5.10.y
source-depth: 1
kernel-kdefconfig: [imx8_var_defconfig, snappy/generic.config, snappy/security.config, snappy/systemd.config, snappy/snappy.config, snappy/containers.config ]
kernel-kconfigs:
- CONFIG_LOCALVERSION="-v0.8"
- CONFIG_SYSFS=y
- CONFIG_GPIO_SYSFS=y
- CONFIG_GPIO_GENERIC=y
- CONFIG_HW_RANDOM_TPM=m
- CONFIG_TCG_TPM=m
- CONFIG_TCG_TIS_CORE=m
- CONFIG_TCG_TIS_SPI=m
- CONFIG_SECURITYFS=y
- CONFIG_LSM="yama,integrity,apparmor"
- CONFIG_SECURITY_APPARMOR=y
- CONFIG_AUDIT=y
- CONFIG_SECURITY_APPARMOR_BOOTPARAM_VALUE=1
- CONFIG_DEFAULT_SECURITY_APPARMOR=y
- CONFIG_SYN_COOKIES=y
- CONFIG_STRICT_DEVMEM=y
- CONFIG_DEBUG_RODATA=y
- CONFIG_CC_STACKPROTECTOR=y
- CONFIG_CC_STACKPROTECTOR_STRONG=y
- CONFIG_DEBUG_SET_MODULE_RONX=n
- CONFIG_ENCRYPTED_KEYS=y
- CONFIG_SQUASHFS_XATTR=y
- CONFIG_SQUASHFS_XZ=y
- CONFIG_DEVPTS_MULTIPLE_INSTANCES=y
- CONFIG_TMPFS_XATTR=y
- CONFIG_TMPFS_POSIX_ACL=y
override-pull: |
snapcraftctl pull
set -e
echo "Applying Ubuntu Core AppArmor patches to the kernel..."
git apply -v ../../../patches/apparmor-patch-510.patch
git apply -v ../../../patches/configs-patch-510.patch
snapcraftctl set-version "20-8"
kernel-initrd-compression: lz4
kernel-initrd-firmware:
- firmware/imx/sdma/sdma-imx7d.bin
kernel-device-trees: [ freescale/imx8mp-device-tree-for-kernel ]
kernel-image-target: Image
kernel-with-firmware: false
kernel-add-ppa: true
kernel-initrd-stage-firmware: true
organize:
kernel.img: Image
after: [ firmware ]
build-packages:
- cpio
- libc6-dev
- bison
- flex
- lzop
- libssl-dev
- on amd64 to arm64:
- gcc-aarch64-linux-gnu:amd64
#TODO Strip most firmwares out to make kernel smaller.
firmware:
plugin: nil
source: linux-firmware
override-build: |
mkdir -p $SNAPCRAFT_PART_INSTALL/firmware
cp -av ../../../linux-firmware/* $SNAPCRAFT_PART_INSTALL/firmware/
build-packages:
- zstd
- bison
- device-tree-compiler
- dpkg-dev
- flex
- initramfs-tools-core
- libfdt-dev
- libssl-dev
- lzop
- python3-crypto
- python3-pycryptodome
- python3-pyelftools
- python3-serial
- u-boot-tools
- wget
- libjson-c-dev
- binutils-${SNAPCRAFT_ARCH_TRIPLET}
- gcc-${SNAPCRAFT_ARCH_TRIPLET}
```
### Relevant log output
```shell
+ '[' -d /home/ubuntu/kernel/parts/kernel/src/kernel ']'
+ KERNEL_SRC=/home/ubuntu/kernel/parts/kernel/src
+ echo PATH=/snap/snapcraft/13058/libexec/snapcraft:/snap/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
PATH=/snap/snapcraft/13058/libexec/snapcraft:/snap/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
+ echo KERNEL_SRC=/home/ubuntu/kernel/parts/kernel/src
KERNEL_SRC=/home/ubuntu/kernel/parts/kernel/src
+ initrd_installed_kernel_modules=
+ initrd_configured_kernel_modules=
+ echo 'Getting ubuntu-core-initrd....'
Getting ubuntu-core-initrd....
+ '[' '!' -e /home/ubuntu/kernel/parts/kernel/build/ubuntu-core-initramfs ']'
+ download_core_initrd arm64 /home/ubuntu/kernel/parts/kernel/build/ubuntu-core-initramfs
+ apt-get download ubuntu-core-initramfs:arm64
Get:1 http://ppa.launchpad.net/snappy-dev/image/ubuntu focal/main arm64 ubuntu-core-initramfs arm64 51.15 [18.2 MB]
Fetched 18.2 MB in 48s (381 kB/s)
W: Download is performed unsandboxed as root as file '/home/ubuntu/kernel/parts/kernel/build/ubuntu-core-initramfs_51.15_arm64.deb' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
+ dpkg -x ubuntu-core-initramfs_51.15_arm64.deb /home/ubuntu/kernel/parts/kernel/build/ubuntu-core-initramfs
+ echo 'Getting snapd deb for snap bootstrap...'
Getting snapd deb for snap bootstrap...
+ '[' '!' -e /home/ubuntu/kernel/parts/kernel/build/ubuntu-core-initramfs/usr/lib/snapd ']'
+ download_snap_bootstrap arm64 /home/ubuntu/kernel/parts/kernel/build/ubuntu-core-initramfs
+ apt-get download snapd:arm64
E: Can't select candidate version from package snapd:arm64 as it has no candidate
Failed to build 'kernel'.
Recommended resolution:
Check the build logs and ensure the part's configuration and sources are correct.
```
### Additional context
_No response_
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| stealth/space-bunny-alpha |
Impact:
45
Quick Win:
14
Complexity:
62
Confidence:
87
Actionability:
82
|
needs triage | ARM64 core20 kernel cross-builds fail while fetching snapd:arm64; a minimal apt reproducer exists, but the report has no maintainer triage or release mapping. | |
| qwen/qwen3.6-35b-a3b |
Impact:
20
Quick Win:
14
Complexity:
10
Confidence:
80
Actionability:
80
|
close not a bug | User reports snapcraft failing to cross-compile ARM64 kernel because apt cannot download snapd:arm64 package from configured repositories | |
| qwen/qwen3.8-27b |
Impact:
40
Quick Win:
18
Staleness:
78
Complexity:
55
Confidence:
55
Support Request:
25
|
needs triage | Cross-compiling an ARM64 kernel with snapcraft 7.5.8/8.5.1 fails when the kernel plugin runs 'apt-get download snapd:arm64' for snap bootstrap, because the Focal build environment has no snapd arm64 candidate. No maintainer response; reporter reproduced the apt error on Ubuntu 20/22 in Jan 2025. | |
| qwen/qwen3.6-35b-a3b |
Staleness:
95
Complexity:
45
Confidence:
90
Support Request:
85
|
close not a bug | Cross-compiling ARM64 kernels with snapcraft fails when downloading snapd:arm64. Inactive for over 1.5 years with no maintainer response. Author identified the root cause as an external apt repository issue rather than a snapcraft defect. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
95
Complexity:
15
Confidence:
85
Support Request:
90
|
close not a bug | Cross-compiling ARM64 kernel fails due to apt-get download snapd:arm64 error. Author identifies it as an apt repository configuration issue rather than a snapcraft bug. |
Update history
No update history recorded yet.
Related work
-
Related To:
snapcraft#6237
(confidence 90%)
Kernel-plugin migration history touches the legacy `download_snap_bootstrap` path, which is absent from the current implementation.
-
Related To:
snapcraft#5814
(confidence 78%)
Introduced the current kernel and initrd plugin implementation, replacing the legacy code path that issued `apt-get download snapd:arm64`.
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #2012074 snapcraft cannot build snap by default on aarch64 | snapcraft (launchpad) | open | ARM64 default builds failed on Snapcraft 7.3.1 because core20 selected amd64-only Multipass images; later defaults use core22/LXD on Linux, addressing the reported path. | |
| #1757094 snapcraft in edge channel (2.39.2+git46.c22d7e2) fails to cross-compile kernel | snapcraft (launchpad) | closed | Cross-compile priming was fixed by snapcore/snapcraft#2012, merged as eae356003, skipping ELF dependency and linker checks for non-app snaps such as kernel snaps. | |
| #2099923 Snapcraft builds are failing: install of snap "snapcraft" failed | snapcraft (launchpad) | open | Reported Launchpad Bionic non-i386 builds cannot install Snapcraft 7.x/stable because core20 needs snapd 2.61; the issue remains open, untriaged, and unanswered. | |
| #2015091 snapcraft download debian package from incorrect arch | snapcraft (launchpad) | open | Cross-building for arm64 on amd64 resolved explicitly qualified bsdmainutils:arm64 to an amd64 package; the valid report remains untriaged and a similar bug is still open. | |
| #1866300 snapcraft fails to build core20 snap | snapcraft (launchpad) | closed | Closed without a documented fix after core20 Multipass/LXD failures; core20 build-base support was unavailable and the workaround was destructive mode. | |
| #1943603 snapcraft --target-arch=i386 does not build i386 images, because core20 does not support i386 and yet the build starts and wastes time | snapcraft (launchpad) | open | Legacy Snapcraft accepted an unsupported core20/i386 target, wasted build time, and produced an amd64 snap; current validation excludes i386 and drops core20. | |
| #1641123 snapcraft does not properly detect the architecture when kernel is 64 bits but userspace is 32 | snapcraft (launchpad) | closed | Fixed in snapcore/snapcraft#1089 by deriving the build architecture from the compiler target, preventing 32-bit ARM artifacts from being mislabeled arm64. | |
| #5638 Snapcraft fails to run on 32bit userspace container on 64bit ARM kernel. | snapcraft | closed | Fixed by merged PR #6394 (commit e51640488): Snapcraft now maps armv8l to armv7l, supporting ARMHF builds in 32-bit ARM userspace on 64-bit ARM kernels. | |
| #1569280 Snapcraft fails to strip go binaries on arm | snapcraft (launchpad) | closed | ARM cross-builds failed when ELF crawling ran ldd on Go binaries; ubuntu-core/snapcraft PR #440 made ldd failures non-fatal. | |
| #1907721 Snapcraft broken on ARM64 | snapcraft (launchpad) | closed | Closed as a configuration issue: a system-wide Python package broke apt-installed Snapcraft, while Multipass lacked ARM64 support; maintainers recommended the Snapcraft snap and --use-lxd. |