ktest setup: GRUB submenu fixes #486
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The GRUB documentation used to say `GRUB_DISABLE_SUBMENU=y`, now it says `GRUB_DISABLE_SUBMENU=true` Also, the corresponding code is unreliable copy/paste/diverge: rhboot/grub2@ee4bd79ef28e6fa4a6 This makes GRUB submenus error-prone. As a broken grub.cfg makes the system unbootable, "harden" the corresponding documentation. Signed-off-by: Marc Herbert <[email protected]>
marc-hb
requested review from
lgirdwood,
deb-intel,
intelkevinputnam,
mmaka1 and
mwasko
as code owners
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| echo 'GRUB_DISABLE_SUBMENU=y' | sudo tee -a /etc/default/grub.d/disable-submenu.cfg |
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the commit is saying that GRUB_DISABLE_SUBMENU=true is the documented setting and not with y?
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- The documentation changed from
y(unusual) totrue(common) - The _implementation changed from: "
yonly" to: "yORtrue".
=> To be compatible with ALL grub versions, stick to y.
| @@ -84,7 +92,7 @@ Set up a target | |||
| # Print your currently booted (and known-safe) option | |||
| cat /proc/cmdline | |||
| # List the grub entries | |||
| awk '/^menuentry/ { print i++, '\t', $0 }' /boot/grub/grub.cfg | |||
| awk '/^menuentry|submenu/ { print i++, '\t', $0 }' /boot/grub/grub.cfg | |||
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there should not be any submenu at this point?
But sudo might be needed to actually read the grub.cfg
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there should not be any submenu at this point?
Not in theory.
In practice this "magic" command is typically re-used across devices - including devices that still have submenus for whatever reason. And the consequences can be deadly.
But sudo might be needed to actually read the grub.cfg
In my experience it's not; I use this command all the time.
| # Better safe than _very_ sorry | ||
| sudo cp /boot/grub/grub.cfg /boot/grub/saved_grub.cfg | ||
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| sudo update-grub |
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Note: this sometimes can cause un-bootable system which can be only recovered by booting to a live env, chrooting to the existing linux install and grub-install --target=x86_64-efi ....
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I tried to chroot and run update-grub inside the chroot but that did not work, it failed with: can't find device for /, is /dev mounted?
GRUB was still installed fine on my system in that instance, that wasn't my problem.
What worked for me was to find and manually enter grub commands and parameters at boot time. This let me boot. Then I disabled the submenus and ran update-grub from the "real" system.
Different OS and different situations will require different solutions. Rescuing unbootable systems is a very complex topic; we can't provide bullet proof advice in such a limited space here.
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I tried to chroot and run update-grub inside the chroot but that did not work, it failed with:
can't find device for /, is /dev mounted?GRUB was still installed fine on my system in that instance, that wasn't my problem.
Few things should be done to be able to update grub in chroot, something like:
https://wiki.gentoo.org/wiki/Chroot#Configuration
What worked for me was to find and manually enter grub commands and parameters at boot time.
Wow
This let me boot. Then I disabled the submenus and ran
update-grubfrom the "real" system.Different OS and different situations will require different solutions. Rescuing unbootable systems is a very complex topic; we can't provide bullet proof advice in such a limited space here.
Sure!
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@marc-hb Are you ready for this PR to be merged? Thanks.
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@ujfalusi Has the issues you raised been resolved to your satisfaction? If so, I will merge this PR. |
The GRUB documentation used to say
GRUB_DISABLE_SUBMENU=y, now it saysGRUB_DISABLE_SUBMENU=trueAlso, the corresponding code is unreliable copy/paste/diverge:
rhboot/grub2@ee4bd79ef28e6fa4a6
This makes GRUB submenus error-prone. As a broken grub.cfg makes the system unbootable, "harden" the corresponding documentation.