Add crashkernel support

[Kai-Heng Feng]

To collect kernel panic when userspace processes are frozen, we can use crashkernel to collect log:
$ sudo apt-get install linux-crashdump

And the panic log will be put in /var/crash, if a kernel panic ever happened.

[Sylvain Pineau (sylvain-pineau)]

Is it just a matter of adding linux-crashdump as a dependency?

[Kai-Heng Feng (kaihengfeng)]

Also needs to upload the panic log from /var/crash/

Maybe leverage apport? It already has a hook for linux-crashdump.

[Kai-Heng Feng (kaihengfeng)]

Manually trigger a panic to see how it works:
# echo c > /proc/sysrq-trigger

[Rex Tsai (chihchun)]

There are a few things that should be considered.

= Setup =
- the linux-crashdump need to be installed.
- kdump should be enabled by /etc/default/kdump-tools or dpkg-configurate.
- kexec-tools will be installed, but we don't want kexec-tools handle reboots, only use kexe for kdump.
- the system needs to have enough memory to load the kernel and save the crash file, the current default settings is 512M-:192M. It may not enough to dump the file. I think Ubuntu should change it using auto[1], and does not store any crash on a machine less than 4G memory.
- we may consider to use kernel panic to capture other sockup issues[2].

= Bug report =
- there are several tools can be used to submit the crash file to launchpad. But I think it would best to use a checkbox test job capture the crash file, and use apport via qabro to submit the bug to launchpad.

[1] [0/7] Implement crashkernel=auto - Patchwork - https://lore.kernel.org/patchwork/cover/166256/
[2] Kernel/CrashdumpRecipe - Ubuntu Wiki - https://wiki.ubuntu.com/Kernel/CrashdumpRecipe

[Pierre Equoy (pieq)]

If Checkbox has a dedicated job that captures the kernel crash log and put it in Checkbox's $PLAINBOX_SESSION_SHARE directory, then it will be captured by QABro when filing a bug, since QABro currently archives the most current Checkbox session on the device and sends it over to Launchpad.

[Scott Hu (huntu207)]

Hi Pierre,

Could you help to investigate that captures the kernel crash log from /var/crash/ directly when QABro file a bug? Due to it seems need more effort to determine when should the job puts the kernel panic log to Checkbox's $PLAINBOX_SESSION_SHARE

[Maksim Beliaev (beliaev-maksim)]

Bug was migrated to GitHub: https://github.com/canonical/checkbox/issues/147.
Bug is no more monitored here.