My dell vostro 3267 desktop machine (Pentium G4560) is frozen with drm-next-kmod 4.11.g20180822 on r338436 or after. It was good working on r338435 or before. I can boot with commenting out the kld_list="/boot/modules/i915kms.ko" in /etc/rc.conf. After booted, kldload /boot/modules/i915kms.ko makes this machine to freeze.
I found that recompiling and reinstalling graphics/drm-next-kmod solves this problem.