After upgrade to Silverblue 40 boot hangs to "ext4: Unknown parameter 'subvol'"


Upgraded Silverblue 39 to 40, and now when booting to 40 the boot hangs, last messages are:

ext3: Unknown parameter 'subvol'

ext2: Unknown parameter 'subvol'

ext4: Unknown parameter 'subvol'

Booting to 39 still works. Do you have any clue how to fix this?

Can you share the content of your /etc/fstab? subvol is for btrfs volumes as far as I know so this is weird.

Thank you for your quick reply! Here is the content of /etc/fstab

UUID=a3e56928-37a1-4e97-886a-158fe72d9a05 /                       btrfs   subvol=root,noatime,compress=zstd:1,x-systemd.device-timeout=0 0 0
UUID=e7c11371-e83b-4442-ab81-1538c3a861dd /boot                   ext4    defaults        1 2
UUID=61E8-9A73          /boot/efi               vfat    umask=0077,shortname=winnt 0 2
UUID=a3e56928-37a1-4e97-886a-158fe72d9a05 /home                   btrfs   subvol=home,noatime,compress=zstd:1,x-systemd.device-timeout=0 0 0
UUID=a3e56928-37a1-4e97-886a-158fe72d9a05 /var                    btrfs   subvol=var,noatime,compress=zstd:1,x-systemd.device-timeout=0 0 0

OK, then it’s likely something else. Can you boot back into Fedora 39 and get the full log from the previous boot?

You should be able to use Ctrl+Alt+Del to force a reboot that will still write the logs to the disk.


This time I hit Ctrl+Alt+Del and managed to get more information, but it did not force reboot, so it seems I can’t deliver full log. There is something “VFS: Can not open rootdevice”

It looks like it can not find the root partition / disk. Did you change anything related?

Can you boot back to Fedora 39 and paste here your GRUB config from /boot?

I did do this, it works with 39 but I don’t know if it is related:

sudo sed -i 's/compress=zstd:1/noatime,compress=zstd:1/' /etc/fstab

Here is grub.cfg:

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub2-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
set pager=1

if [ -f ${config_directory}/grubenv ]; then
  load_env -f ${config_directory}/grubenv
elif [ -s $prefix/grubenv ]; then
  load_env
fi
if [ "${next_entry}" ] ; then
   set default="${next_entry}"
   set next_entry=
   save_env next_entry
   set boot_once=true
else
   set default="${saved_entry}"
fi

if [ x"${feature_menuentry_id}" = xy ]; then
  menuentry_id_option="--id"
else
  menuentry_id_option=""
fi

export menuentry_id_option

if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}

function load_video {
  if [ x$feature_all_video_module = xy ]; then
    insmod all_video
  else
    insmod efi_gop
    insmod efi_uga
    insmod ieee1275_fb
    insmod vbe
    insmod vga
    insmod video_bochs
    insmod video_cirrus
  fi
}

terminal_output console
if [ x$feature_timeout_style = xy ] ; then
  set timeout_style=menu
  set timeout=5
# Fallback normal timeout code in case the timeout_style feature is
# unavailable.
else
  set timeout=5
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/01_users ###
if [ -f ${prefix}/user.cfg ]; then
  source ${prefix}/user.cfg
  if [ -n "${GRUB2_PASSWORD}" ]; then
    set superusers="root"
    export superusers
    password_pbkdf2 root ${GRUB2_PASSWORD}
  fi
fi
### END /etc/grub.d/01_users ###

### BEGIN /etc/grub.d/08_fallback_counting ###
insmod increment
# Check if boot_counter exists and boot_success=0 to activate this behaviour.
if [ -n "${boot_counter}" -a "${boot_success}" = "0" ]; then
  # if countdown has ended, choose to boot rollback deployment,
  # i.e. default=1 on OSTree-based systems.
  if  [ "${boot_counter}" = "0" -o "${boot_counter}" = "-1" ]; then
    set default=1
    set boot_counter=-1
  # otherwise decrement boot_counter
  else
    decrement boot_counter
  fi
  save_env boot_counter
fi
### END /etc/grub.d/08_fallback_counting ###

### BEGIN /etc/grub.d/10_linux ###
insmod part_gpt
insmod ext2
search --no-floppy --fs-uuid --set=root e7c11371-e83b-4442-ab81-1538c3a861dd
insmod part_gpt
insmod fat
search --no-floppy --fs-uuid --set=boot 61E8-9A73

# This section was generated by a script. Do not modify the generated file - all changes
# will be lost the next time file is regenerated. Instead edit the BootLoaderSpec files.
#
# The blscfg command parses the BootLoaderSpec files stored in /boot/loader/entries and
# populates the boot menu. Please refer to the Boot Loader Specification documentation
# for the files format: https://systemd.io/BOOT_LOADER_SPECIFICATION/.

# The kernelopts variable should be defined in the grubenv file. But to ensure that menu
# entries populated from BootLoaderSpec files that use this variable work correctly even
# without a grubenv file, define a fallback kernelopts variable if this has not been set.
#
# The kernelopts variable in the grubenv file can be modified using the grubby tool or by
# executing the grub2-mkconfig tool. For the latter, the values of the GRUB_CMDLINE_LINUX
# and GRUB_CMDLINE_LINUX_DEFAULT options from /etc/default/grub file are used to set both
# the kernelopts variable in the grubenv file and the fallback kernelopts variable.
if [ -z "${kernelopts}" ]; then
  set kernelopts="root=UUID=a3e56928-37a1-4e97-886a-158fe72d9a05 ro rootflags=subvol=root/ostree/deploy/fedora/deploy/47ee8b8ed4b52481059e2d56824bfe255d6f780f79151e7e51f8cc570fdfd774.0 rd.luks.uuid=luks-d11e47de-476b-471f-b147-811081a6999e rhgb quiet "
fi

insmod blscfg
blscfg
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/10_reset_boot_success ###
# Hiding the menu is ok if last boot was ok or if this is a first boot attempt to boot the entry
if [ "${boot_success}" = "1" -o "${boot_indeterminate}" = "1" ]; then
  set menu_hide_ok=1
else
  set menu_hide_ok=0 
fi
# Reset boot_indeterminate after a successful boot
if [ "${boot_success}" = "1" ] ; then
  set boot_indeterminate=0
# Avoid boot_indeterminate causing the menu to be hidden more than once
elif [ "${boot_indeterminate}" = "1" ]; then
  set boot_indeterminate=2
fi
# Reset boot_success for current boot 
set boot_success=0
save_env boot_success boot_indeterminate
### END /etc/grub.d/10_reset_boot_success ###

### BEGIN /etc/grub.d/12_menu_auto_hide ###
if [ x$feature_timeout_style = xy ] ; then
  if [ "${menu_show_once}" ]; then
    unset menu_show_once
    save_env menu_show_once
    set timeout_style=menu
    set timeout=60
  elif [ "${menu_auto_hide}" -a "${menu_hide_ok}" = "1" ]; then
    set orig_timeout_style=${timeout_style}
    set orig_timeout=${timeout}
    if [ "${fastboot}" = "1" ]; then
      # timeout_style=menu + timeout=0 avoids the countdown code keypress check
      set timeout_style=menu
      set timeout=0
    else
      set timeout_style=hidden
      set timeout=1
    fi
  fi
fi
### END /etc/grub.d/12_menu_auto_hide ###

### BEGIN /etc/grub.d/14_menu_show_once ###
if [ x$feature_timeout_style = xy ]; then
  if [ "${menu_show_once_timeout}" ]; then
    set timeout_style=menu
    set timeout="${menu_show_once_timeout}"
    unset menu_show_once_timeout
    save_env menu_show_once_timeout
  fi
fi
### END /etc/grub.d/14_menu_show_once ###

### BEGIN /etc/grub.d/15_ostree ###
menuentry 'Fedora Linux 40.20240426.0 (Silverblue) (ostree:0)' --class gnu-linux --class gnu --class os --unrestricted 'ostree-0-e7c11371-e83b-4442-ab81-1538c3a861dd' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_gpt
insmod ext2
search --no-floppy --fs-uuid --set=root e7c11371-e83b-4442-ab81-1538c3a861dd
linux16 /ostree/fedora-616c96a50fce33c3ca036243212c6899d95f31761f518a8f4a8e9aff8f716433/vmlinuz-6.8.7-300.fc40.x86_64 rd.luks.uuid=luks-d11e47de-476b-471f-b147-811081a6999e rhgb quiet root=UUID=a3e56928-37a1-4e97-886a-158fe72d9a05 rootflags=subvol=root rw ostree=/ostree/boot.0/fedora/616c96a50fce33c3ca036243212c6899d95f31761f518a8f4a8e9aff8f716433/0 rd.luks.options=d11e47de-476b-471f-b147-811081a6999e=discard
initrd16 /ostree/fedora-616c96a50fce33c3ca036243212c6899d95f31761f518a8f4a8e9aff8f716433/initramfs-6.8.7-300.fc40.x86_64.img
}
menuentry 'Fedora Linux 39.20240426.0 (Silverblue) (ostree:1)' --class gnu-linux --class gnu --class os --unrestricted 'ostree-1-e7c11371-e83b-4442-ab81-1538c3a861dd' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_gpt
insmod ext2
search --no-floppy --fs-uuid --set=root e7c11371-e83b-4442-ab81-1538c3a861dd
linux16 /ostree/fedora-81ec6031e009fb1aeca2fe3b2b541025447ddd72ef100b5dda1f74b23757d0cb/vmlinuz-6.8.7-200.fc39.x86_64 rd.luks.uuid=luks-d11e47de-476b-471f-b147-811081a6999e rhgb quiet root=UUID=a3e56928-37a1-4e97-886a-158fe72d9a05 rootflags=subvol=root rw ostree=/ostree/boot.0/fedora/81ec6031e009fb1aeca2fe3b2b541025447ddd72ef100b5dda1f74b23757d0cb/0 rd.luks.options=d11e47de-476b-471f-b147-811081a6999e=discard
initrd16 /ostree/fedora-81ec6031e009fb1aeca2fe3b2b541025447ddd72ef100b5dda1f74b23757d0cb/initramfs-6.8.7-200.fc39.x86_64.img
}
### END /etc/grub.d/15_ostree ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/20_ppc_terminfo ###
### END /etc/grub.d/20_ppc_terminfo ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/30_uefi-firmware ###
if [ "$grub_platform" = "efi" ]; then
	menuentry 'UEFI Firmware Settings' $menuentry_id_option 'uefi-firmware' {
		fwsetup
	}
fi
### END /etc/grub.d/30_uefi-firmware ###

### BEGIN /etc/grub.d/35_fwupd ###
### END /etc/grub.d/35_fwupd ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f  ${config_directory}/custom.cfg ]; then
  source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f  $prefix/custom.cfg ]; then
  source $prefix/custom.cfg
fi
### END /etc/grub.d/41_custom ###

While booting there has been also this after Grub:

error: ../../grub-core/kern/mm.c:376:out of memory.

Press any key to continue...

But 39 boots regardles of that.