[Hyper-V] kdump is broken on trusty with linux-azure 4.15.0-1032 kernel

[Chris Valean]

While testing linux-azure 4.15.0-1032 kernel from proposed we found that kdump is no longer working as expected, on trusty only.

Here are some info and versions.
We'll have to verify a few more scenarios with other images and try to isolate this, but as least the kdump on trusty issue is there.
Also remains to be checked in which release this regression was introduced.
The below can be repro'd on Azure.

On Xenial it works with ubuntu provided latest kexec-tools 2.0.16.

It looks like the kexec might require some patches from upstream as far as I can tell from the data we have so far.

Distro / kernel: 4.15.0-1032-azure #33~14.04.2-Ubuntu
Package: kdump-tools 1.5.5-2ubuntu1.6

Errors from logs:
kdump-config: failed to load kdump kernel
kernel: [ 230.772409] init: kdump-tools main process (1726) terminated with status 1

# cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-4.15.0-1032-azure root=x ro console=tty1 console=ttyS0 earlyprintk=ttyS0 rootdelay=300 crashkernel=384M

---

This issue looks resolved with the kexec package build from the official kernel.org kexec repo, on top of 14.04.

kexec-tools 2.0.18
https://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git

# cat /sys/kernel/kexec_*
1
402653184
And kdump core file gets created when running with 1032 kernel.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Chris Valean (cvalean)]

Issue remains in latest 4.15.0-1040-azure.
No new version for kdump-tools - latest 1.5.5-2ubuntu1.6.