Description:
Systemd hangs on boot with certain grsecurity hardened kernels. The issue arose near the end of 2016, and has persisted sporadically. The issue comes during boot, systemd creates, mounts, and then chdirs into a tmpfs. Immediately thereafter, the function fails, and repeats. The result is that it just mounts and unmounts the tmpfs until the system hangs. I've been working on it with the grsecurity team, here: https://forums.grsecurity.net/viewtopic.php?f=3&t=4676
I've also got a picture of the issue here: https://drive.google.com/file/d/0B7y3E9VTFdy4SjRvZ05BZkcxQjg/view?usp=sharing

The issue was resolved in the 5 and 12 March patchsets, but arose again in the 15 March patchset. It does not occur in the kernel built for the repos by nning. Interestingly, even using nning's configureation file can yield a kernel that causes this error.

I know that this isn't the most informative bug report, but it happens during boot, before I can get to a terminal or anything, so my ability to get logs is limited.
I think it's at least similar to this: https://bugzilla.redhat.com/show_bug.cgi?id=1075835

Additional info:
* package version(s)
Currently, the kernel is 4.9.15
systemd: 232-8
Again, this arose near the end of 2016, at which point the kernel was around 4.8.10 or so, I'm not sure where systemd was at.

* config and/or log files etc.
See the images and links above.

Steps to reproduce:
Build a recent version of the grsecurity kernel -- not every version causes this. The patchset from 15 March does, the patchset from 12 March does not. The issue started to pop-up intermittently around the 4.8.10 patchset.