Hello,

But couldn't grub recover from the error a bit better? It shows in a infinite loop (looks like infinite) the error:

"fatal error: token too large, exceeds YYLMAX"

...and it is impossible (as far as I know) to fix without booting from an different drive or similar to edit the config.

Could it just fail and leave you in a grub prompt? Bonus points if it lets you see the configuration you have and edit it. And more bonus points if the same parsing that it uses during boot to show the YYLMAX error is used in grub-mkconfig or a new grub-checkconfig is created.

Regards

Hello,

I had two single quotes closing a variable in /etc/default/grub like this (due to copy paste mistake from me):

# head /etc/default/grub
#GRUB_DEFAULT=0
GRUB_DEFAULT='Arch Linux, with Linux linux''
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="Arch"
GRUB_CMDLINE_LINUX_DEFAULT="quiet"
GRUB_CMDLINE_LINUX=""

# Preload both GPT and MBR modules so that they are not missed
GRUB_PRELOAD_MODULES="part_gpt part_msdos"

When running grub-mkconfig with that configuration, this is the output:

# sudo grub-mkconfig -o /boot/grub/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-linux-lts
Found initrd image: /boot/initramfs-linux-lts.img
Found fallback initramfs image: /boot/initramfs-linux-lts-fallback.img
Found linux image: /boot/vmlinuz-linux-git
Found initrd image: /boot/initramfs-linux-git.img
Found fallback initramfs image: /boot/initramfs-linux-git-fallback.img
Found linux image: /boot/vmlinuz-linux
Found initrd image: /boot/initramfs-linux.img
Found fallback initramfs image: /boot/initramfs-linux-fallback.img
Found CentOS Linux release 7.2.1511 (Core)  on /dev/mapper/cc_pb--d--128--141--150--49-root
done


As you can see there is no error, but the resulting file has a missing double quote (at set default="Arch Linux, with Linux linux):

# sudo head /boot/grub/grub.cfg -n 25
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -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="Arch Linux, with Linux linux
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="Arch"
GRUB_CMDLINE_LINUX_DEFAULT="quiet"
GRUB_CMDLINE_LINUX=""

# Preload both GPT and MBR modules so that they are not missed
GRUB_PRELOAD_MODULES="part_gpt part_msdos"


When booting an error is displayed in loop and the only option is to reboot:

"fatal error: token too large, exceeds YYLMAX"