freebsd stable - Jun 2018 - regression: tmpfs in /etc/fstab results in boot stoppage

Hi,

I've updated to r335297 on STABLE-11. My root fs is ZFS, and /etc/fstab is:

# Device                Mountpoint      FStype  Options         Dump    Pass#
/dev/gpt/irontree-swap  none            swap    sw              0       0
tmpfs                   /home/jonc/.cache tmpfs rw,size=512m,late       0 2

My /etc/rc.conf also contains:
background_fsck="NO"

When I reboot the system, the kernel boots; but the startup scripts fail with:

fsck: exec fsck_tmpfs for tmpfs in /sbin/:/usr/sbin: No such file or directory
THE FOLLOWING FILE SYSTEM HAD AN UNEXPECTED INCONSISTENCY:
  tmpfs: tmpfs (/home/jonc/.cache)

The system continues booting up as usual once I exit single-user mode.
The system used to boot up with any intervention prior to this.

Cheers.
-- 
Jonathan Chen <jonc at chen.org.nz>

On Mon, Jun 18, 2018 at 08:46:35AM +1200, Jonathan Chen
wrote:
> Hi,
> 
> I've updated to r335297 on STABLE-11. My root fs is ZFS, and /etc/fstab
is:
> 
> # Device                Mountpoint      FStype  Options         Dump   
Pass#
> /dev/gpt/irontree-swap  none            swap    sw              0       0
> tmpfs                   /home/jonc/.cache tmpfs rw,size=512m,late       0 2
> 
> My /etc/rc.conf also contains:
> background_fsck="NO"
> 
> When I reboot the system, the kernel boots; but the startup scripts fail
with:
> 
> fsck: exec fsck_tmpfs for tmpfs in /sbin/:/usr/sbin: No such file or
directory
> THE FOLLOWING FILE SYSTEM HAD AN UNEXPECTED INCONSISTENCY:
>   tmpfs: tmpfs (/home/jonc/.cache)
> 
> The system continues booting up as usual once I exit single-user mode.
> The system used to boot up with any intervention prior to this.
You specified fsck pass for tmpfs mount, which makes no sense and cannot
work since there is no fsck_tmpfs.  Fix you fstab.