Comment 21 for bug 1917894

[Bionic regression / autopkgtest]

simple.sh is looking if it doesn't load module by happenstance by comparing the list before and after, and Bionic w/ 4.15 kernel reveal that 'devlink' is added along the way. I was able to isolate it to the networking plugin:

root@srv:~# lsmod | grep -i devlink
root@srv:~# sos report -o networking

sosreport (version 4.1)

.....

Your sosreport has been generated and saved in:
 /tmp/sosreport-srv-2021-03-31-tvjgeyv.tar.xz

 Size 29.75KiB
 Owner root
 sha256 72d49c26463f8fe42f11696dbc69aaa6eaf4e621551d88822b72a6f27ed7a136

Please send this file to your support representative.

More precisely to this specific code line:
https://github.com/sosreport/sos/blob/master/sos/report/plugins/networking.py#L109

# Manual reproducer:
root@srv:~# lsmod | grep -i devlink
root@srv:~# devlink dev
root@srv:~# lsmod | grep -i devlink
devlink 45056 0

I can reproduce the behaviour every time only on 4.15 but not on more recent kernel (5.4).

I highly suspect that this is due to following kernel configuration:

config-4.15.0-140-generic:CONFIG_MAY_USE_DEVLINK=m
config-5.4.0-70-generic:CONFIG_NET_DEVLINK=y

With that being said, it is safe to ignore the failure here for now as it has nothing to do with sosreport. I already addressed it with sos upstream. And I'll try work on mitigation/workaround in sosreport eventually, maybe using SoSpredicate or some sort.

- Eric