[Bug 1835660] Re: initramfs unpacking failed

[Dimitri John Ledkov]

@Siarhei

That looks very valid. And we were close to getting to that, when apw &
I timed out looking at this.

lz4 -l     Use Legacy format (typically for Linux Kernel compression)
              Note : -l is not compatible with -m (--multiple) nor -r

Which must always be used when creating initrd. Ideally, both userspace
output and linux kernel consumption should agree what said legacy format
should look like and what it must produce and consume.

Is https://github.com/lz4/lz4/blob/dev/doc/lz4_Frame_format.md#legacy-
frame underspecified, or does lz4 produce non-compliant frames, or
kernel misprocesses compliant frames?

Also, can we upgrade lz4 in the kernel tree to 1.9.2?

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https://bugs.launchpad.net/bugs/1835660

Title:
  initramfs unpacking failed

Status in OEM Priority Project:
  New
Status in initramfs-tools package in Ubuntu:
  Invalid
Status in linux package in Ubuntu:
  Confirmed

Bug description:
  "initramfs unpacking failed: Decoding failed",  message appears on
  boot up.

  If I "update-initramfs" using gzip instead of lz, then boot up passes
  without decoding failed message.

  ---

  However, we currently believe that the decoding error reported in
  dmesg is actually harmless and has no impact on usability on the
  system.

  Switching from lz4 to gzip compression, simply papers over the
  warning, without any benefits, and slows down boot.

  Kernel should be fixed to correctly parse lz4 compressed initrds, or
  at least lower the warning, to not be user visible as an error.

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