bcache kernel oops

[step21]

This was on an 18.04.1 install running the hwe 4.15-34 generic kernel image, running from a normal ext4 root device.
I had just a short while before create a new bcache device that was mounted but to which no data had been written yet. Then without any apparent particular reason, an apport error popped up to inform of a bcache kernel oops. Crash log was uploaded but no idea how to link it, so I attach it as well.
Mostly I would like to know how concerned I should be as after a previous, successful test I wanted to move the whole install to bcache. Ideally, if this is a bug or similar, it would be nice if it could get fixed.

[step21 (step22)]

It seems that this might be only a problem with linux-image-4.15.0-34-generic
I tested it now with linux-image-4.15.0-34-generic and 4.18.0 (self compiled) and in both cases the oops didn't trigger after a reasonable amount of time.
When checking the changelog for -34 it seems there was a change regarding bcache: bcache: fix kcrashes with fio in RAID5 backend dev
Could this be related to that?

[step21 (step22)]

https://launchpad.net/ubuntu/+source/linux/4.15.0-34.37

[Ken Sharp (kennybobs)]

>bcache: bcache: fix kcrashes with fio in RAID5 backend dev
>Could this be related to that?

Remove that patch and find out.