= Verification =
$ cat versions.txt
5.8.0-50-generic
5.8.0-50-generic-64k
$ for dist in hirsute groovy focal bionic; do
lxc exec dannf-lp1926985-${dist} -- dpkg-query --showformat='${Version}\n'
--show linux-base; lxc exec dannf-lp1926985-${dist} -- linux-version sort <
versions.txt; done
4.5ubuntu5.4
5.8.0-50-generic
5.8.0-50-generic-64k
4.5ubuntu4.1
5.8.0-50-generic
5.8.0-50-generic-64k
4.5ubuntu3.7
5.8.0-50-generic
5.8.0-50-generic-64k
4.5ubuntu1.7
5.8.0-50-generic
5.8.0-50-generic-64k
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Packages, which is subscribed to linux-base in Ubuntu.
https://bugs.launchpad.net/bugs/1926985
Title:
linux-version sort: argv and stdin behaviors differ
Status in linux-base package in Ubuntu:
Fix Released
Status in linux-base source package in Bionic:
Fix Committed
Status in linux-base source package in Focal:
Fix Committed
Status in linux-base source package in Groovy:
Fix Committed
Status in linux-base source package in Hirsute:
Fix Committed
Status in linux-base source package in Impish:
Fix Released
Status in linux-base package in Debian:
New
Bug description:
[Impact]
`linux-version sort` provides 2 ways to sort kernel version strings: users
can provide these strings either via the command line or via stdin. Currently
these methods give different answers for certain version strings (see Test
Case). The stdin behavior is decidedly incorrect, and this is the mode
flash-kernel uses. As a real world example, a user with an arm64 u-boot system
might end up booting 5.8.0-50-generic instead of the expected
5.8.0-50-generic-64k if both are installed. There maybe additional issues
caused by this; for example, I found this with our automation that tests
kernels on various arm64 platforms in version increasing order. Only after
consulting logs did we realize that 64k kernels were not ever getting booted
because the tooling (which uses argv mode) disagreed with the kernel installer
(flash-kernel using stdin mode) about which kernel should be the default.
It's possible this internal discrepancy can cause other issues due to
tools disagreeing about which kernel is the latest, but the flash-
kernel example is the only one I'm aware of at this point.
[Test Case]
Using argv:
$ linux-version sort 5.8.0-50-generic 5.8.0-50-generic-64k
5.8.0-50-generic
5.8.0-50-generic-64k
Using stdin (incorrect):
$ cat versions.txt
5.8.0-50-generic
5.8.0-50-generic-64k
$ cat versions.txt | linux-version sort
5.8.0-50-generic-64k
5.8.0-50-generic
[Where Problems Could Occur]
An obvious place where problems could occur is if someone is relying on
rebooting into the kernel that is incorrectly being sorted greatest. For those
using only Ubuntu kernel packages, the only case I'm aware of is arm64 generic
vs. generic-64k case used in the examples above. The generic-64k flavor is
available in >= 20.10, as well as 20.04-hwe. ARM server users - those most
likely to want the generic-64k flavor - are very unlikely to be using
flash-kernel. The standard for ARM servers is UEFI firmware, which use GRUB and
are unaffected by this change. We found this on an HP m400 platform which is
the only Ubuntu certified u-boot-based arm64 server.
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