Snap Core Cannot be mounted

device
1

When attempting to use a newer version of the Linux kernel on an Ubuntu Core Image from a bootable USB deivce, I see that the core snap does not get properly mounted:

lopezem@localhost:~$ sudo systemctl status snap-core-4917.mount
● snap-core-4917.mount - Mount unit for core, revision 4917
   Loaded: loaded (/etc/systemd/system/snap-core-4917.mount; enabled; vendor preset: enabled)
   Active: inactive (dead) since Mon 2018-07-23 14:43:31 UTC; 154ms ago
    Where: /snap/core/4917
     What: /var/lib/snapd/snaps/core_4917.snap
  Process: 7316 ExecMount=/bin/mount /var/lib/snapd/snaps/core_4917.snap /snap/core/4917 -t squashfs -o nodev,ro,x-gdu.hide (code=exited, status=0/SUCCESS)

Jul 23 14:43:29 localhost.localdomain systemd[1]: Mounting Mount unit for core, revision 4917...
Jul 23 14:43:29 localhost.localdomain systemd[1]: Mounted Mount unit for core, revision 4917.

lopezem@localhost:~$ sudo systemctl status snap-core-4917.mount
● snap-core-4917.mount
   Loaded: not-found (Reason: No such file or directory)
   Active: inactive (dead)

Jul 23 14:44:02 localhost.localdomain systemd[1]: Unmounted Mount unit for core, revision 4917.
Jul 23 14:44:10 localhost.localdomain systemd[1]: Mounting Mount unit for core, revision 4917...
Jul 23 14:44:10 localhost.localdomain systemd[1]: Mounted Mount unit for core, revision 4917.
Jul 23 14:44:13 localhost.localdomain systemd[1]: Unmounted Mount unit for core, revision 4917.
Jul 23 14:44:21 localhost.localdomain systemd[1]: Mounting Mount unit for core, revision 4917...
Jul 23 14:44:21 localhost.localdomain systemd[1]: Mounted Mount unit for core, revision 4917.
Jul 23 14:44:23 localhost.localdomain systemd[1]: Unmounted Mount unit for core, revision 4917.
Jul 23 14:44:32 localhost.localdomain systemd[1]: Mounting Mount unit for core, revision 4917...
Jul 23 14:44:32 localhost.localdomain systemd[1]: Mounted Mount unit for core, revision 4917.
Jul 23 14:44:35 localhost.localdomain systemd[1]: Unmounted Mount unit for core, revision 4917.

Consequently, none of the other snaps can be loaded.

I am creating a Ubuntu-kernel 4.15.0 snap using the following:

git clone https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/bionic
git checkout Ubuntu-4.15.0-28.30

I noticed that there is no directory named kernel/configs/snappy/, perhaps this might be the culprit?

Below is my snapcraft.yaml file:

name: pc-kernel
version: null
version-script: |
    . debian/debian.env
    dpkg-parsechangelog -l $DEBIAN/changelog -S version
summary: The Ubuntu generic Linux kernel
description: This Ubuntu generic Linux kernel
grade: stable
confinement: strict
type: kernel

parts:
  kernel:
    plugin: kernel
    source: .
    source-type: git
    kconfigflavour: generic
    kconfigs:
      - CONFIG_DEBUG_INFO=n
      - CONFIG_MMC_SDHCI=y
      - CONFIG_MMC_SDHCI_PLTFM=y
      - CONFIG_MMC_SDHCI_MSM=y
      - CONFIG_DEBUG_RODATA=y
      - CONFIG_DEBUG_SET_MODULE_RONX=y
    kernel-initrd-modules:
      - squashfs
      - usbcore
      - sd_mod
      - ehci_hcd
      - uhci_hcd
      - ohci_hcd
      - usb_storage
      - scsi_mod
    override-build: |
      cp debian/scripts/retpoline-extract-one \
        $SNAPCRAFT_PART_BUILD/scripts/ubuntu-retpoline-extract-one
      snapcraftctl build
    kernel-with-firmware: false
  firmware:
    plugin: nil
    stage-packages:
      - linux-firmware
    organize:
      lib/firmware: firmware
    prime:
      - -usr
      - -lib
    build-packages:
      - cpio
      - libssl-dev

Any suggestions is much appreciated!

2

would be interesting to find out which file or directory is missing here …

3

It is strange, it keeps unmounting and remounting. I do not see anything in /var/log/* that points to this error. Also it looks like it mounts but immediately unmounts it self as well.

lopezem@localhost:~$ sudo systemctl status snap-core-4917.mount
● snap-core-4917.mount - Mount unit for core, revision 4917
   Loaded: loaded (/etc/systemd/system/snap-core-4917.mount; enabled; vendor preset: enabled)
   Active: active (mounted) since Mon 2018-07-23 15:13:49 UTC; 1s ago
    Where: /snap/core/4917
     What: /dev/loop2
  Process: 30171 ExecMount=/bin/mount /var/lib/snapd/snaps/core_4917.snap /snap/core/4917 -t squashfs -o nodev,ro,x-gdu.hide (code=exited, status=0/SUCCESS)

Jul 23 15:13:49 localhost.localdomain systemd[1]: Mounting Mount unit for core, revision 4917...
Jul 23 15:13:49 localhost.localdomain systemd[1]: Mounted Mount unit for core, revision 4917.
4

Perhaps I am missing some kernel modules. Here is a diff below when running lsmod on v4.4.0 vs v4.15.0

diff --git a/kernel-4.4.txt b/kernel-4.15.txt
index a257319..7ea4119 100644
--- a/kernel-4.4.txt
+++ b/kernel-4.15.txt
@@ -1,49 +1,50 @@
 8250_dw
-ablk_helper
+ac97_bus
 aes_x86_64
 aesni_intel
 ahci
 autofs4
-cfg80211
 coretemp
 crc32_pclmul
 crct10dif_pclmul
 cryptd
+crypto_simd
 dca
 drm
 drm_kms_helper
 fb_sys_fops
-fjes
-gf128mul
 ghash_clmulni_intel
 glue_helper
diff --git a/kernel-4.4.txt b/kernel-4.15.txt
index a257319..7ea4119 100644
--- a/kernel-4.4.txt
+++ b/kernel-4.15.txt
@@ -1,49 +1,50 @@
 8250_dw
-ablk_helper
+ac97_bus
 aes_x86_64
 aesni_intel
 ahci
 autofs4
-cfg80211
 coretemp
 crc32_pclmul
 crct10dif_pclmul
 cryptd
+crypto_simd
 dca
 drm
 drm_kms_helper
 fb_sys_fops
-fjes
-gf128mul
 ghash_clmulni_intel
 glue_helper
 hid
 hid_generic
 i2c_algo_bit
 i2c_hid
-i915_bpo
+i915
 idma64
 igb
 input_leds
-intel_ips
+intel_cstate
 intel_lpss
 intel_lpss_pci
 intel_pmc_ipc
 intel_powerclamp
 intel_punit_ipc
+intel_rapl
+intel_rapl_perf
 intel_telemetry_core
 intel_telemetry_pltdrv
 irqbypass
 kvm
 kvm_intel
 libahci
-lrw
+lpc_ich
 mac_hid
 mei
 mei_me
 mmc_block
+nls_iso8859_1
+pcbc
 pinctrl_broxton
-pinctrl_intel
 pps_core
 ptp
 sdhci
@@ -51,24 +52,33 @@ sdhci_acpi
 sdhci_pci
 shpchp
 snd
+snd_compress
 snd_hda_codec
 snd_hda_codec_generic
 snd_hda_codec_hdmi
 snd_hda_codec_realtek
 snd_hda_core
+snd_hda_ext_core
 snd_hda_intel
 snd_hwdep
 snd_pcm
+snd_pcm_dmaengine
+snd_soc_acpi
+snd_soc_core
+snd_soc_skl
+snd_soc_skl_ipc
+snd_soc_sst_dsp
+snd_soc_sst_ipc
 snd_timer
 soundcore
 spi_pxa2xx_platform
 syscopyarea
 sysfillrect
 sysimgblt
+tpm_crb
 uas
 usb_storage
 usbhid
 video
 virt_dma
-virtio_scsi
 x86_pkg_temp_thermal
5

i doubt this has to do with modules (rather with a missing default config option that changed)…

can you pastebin your full syslog somewhere to a paste service and link it here …
also dmesg output and snap changes will be interesting.