Hi,
Quick follow-up on this:
- first off, Arch devs have updated their kernel config so the next
kernel will not have bpfilter enabled anymore, thus avoiding any
issue.
- having said that, I've found a neasy way to reproduce it in an Arch
VM, in case you're interested :
Boot the latest Arch ISO[1] which now contains a kernel 4.18.5 and do a
very basic installation, pretty much just:
# pacstrap /mnt base
# genfstab -U /mnt >> /mnt/etc/fstab
And of course install your boot loader of choice.
Then boot the brand new system, log in and make sure the helper is
actually started, i.e. `modprobe bpfilter` -- Now halt.
You'll see in the end that systemd complains that it can't
unmount /oldroot (EBUSY), aka the root fs; and that's because of the
bpfilter helper, which wasn't killed because it's seen as a kernel
thread due to its empty command line and therefore not signaled.
Cheers,
[1] https://www.archlinux.org/download/