I updated to 4.4.132-51 default kernel on my 64-bit system. It will no longer
boot. The process tries to wait on 8 startup items over and over. It is
impossible to read everything on the low-resolution boot screen, but I get
messages like:

Sleeping function called from an invalid context in_atomic() irqs_disabled()
BUG: scheduling while atomic: systemd-udevd/220/....
BUG: Workqueue leaked lock or atomic: kworker/6: 
    last function: bpf_done_on_this_cpu

It boots properly using the previous kernel, so I believe this is a kernel bug.