[Bug 1831789] Re: Add "dis_ucode_ldr" to linux boot options for Recovery Mode

[Łukasz Zemczak]

Hello Jeroen, or anyone else affected,

Accepted grub2 into focal-proposed. The package will build now and be
available at https://launchpad.net/ubuntu/+source/grub2/2.04-1ubuntu26.3
in a few hours, and then in the -proposed repository.

Please help us by testing this new package.  See
https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how
to enable and use -proposed.  Your feedback will aid us getting this
update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug,
mentioning the version of the package you tested, what testing has been
performed on the package and change the tag from verification-needed-
focal to verification-done-focal. If it does not fix the bug for you,
please add a comment stating that, and change the tag to verification-
failed-focal. In either case, without details of your testing we will
not be able to proceed.

Further information regarding the verification process can be found at
https://wiki.ubuntu.com/QATeam/PerformingSRUVerification .  Thank you in
advance for helping!

N.B. The updated package will be released to -updates after the bug(s)
fixed by this package have been verified and the package has been in
-proposed for a minimum of 7 days.

** Changed in: grub2 (Ubuntu Focal)
       Status: In Progress => Fix Committed

** Tags added: verification-needed verification-needed-focal

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to grub2 in Ubuntu.
https://bugs.launchpad.net/bugs/1831789

Title:
  Add "dis_ucode_ldr" to linux boot options for Recovery Mode

Status in grub2 package in Ubuntu:
  Fix Released
Status in grub2 source package in Xenial:
  New
Status in grub2 source package in Bionic:
  New
Status in grub2 source package in Focal:
  Fix Committed
Status in grub2 source package in Groovy:
  Fix Released

Bug description:
  [Impact]
  Due to some recent problems with a microcode update which broke booting of some laptops I suggest adding "dis_ucode_ldr" to recovery mode boot options to allow booting after a bad microcode update.

  See the following topics that describe the problems:
   - https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1829620
   - https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/1

  When such problems occur it's very hard to see that the microcode
  loading is the issue, the booting just hangs at the purple screen,
  even removing "quiet splash" or using the recovery option will not
  show the error.

  We'll need to double check that dis_ucode_ldr works as expected across all architectures.
  According to the kernel docs (Documentation/admin-guide/kernel-parameters.txt), dis_ucode_ldr is x86 only, so my guess is that it will be ignored for other architectures. According to the kernel code  (arch/x86/kernel/cpu/microcode/core.c), dis_ucode_ldr works for both AMD and Intel.
  I have some time tomorrow on test this on a ARM device.

  This was also discussed Ubuntu Developer mailing list where it was
  suggested to post this here, see: https://lists.ubuntu.com/archives
  /ubuntu-devel/2019-June/040725.html

  [Test case]
  Check that dis_ucode_ldr is present on Linux entries

  [Regression potential]
  If you actually require microcode updates to get into userspace, your recovery option won't work anymore. Does this happen? Seems unlikely.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1831789/+subscriptions