I realize this report is practically useless, but better out than in (according to Shrek). I found this in the logs of my GCE VM running syzkaller bot. No further details were preserved...
2018/11/24 09:53:48 ci-openbsd-main: poll: 94bf4886dbb69e9fbf0f92f975fc23f16fc5c80f 2018/11/24 09:53:48 ci-openbsd-main: building kernel... 2018/11/24 09:54:03 ci-openbsd-main: testing image... 2018/11/24 10:04:07 ci-openbsd-main: VM boot failed with: panic: pvclock0: unstable result on stable clock The host is running OpenBSD 6.4-current (GENERIC.MP) #456: Tue Nov 20 08:46:59 MST 2018 dera...@amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/GENERIC.MP The VM kernel at the time was built at "zap 10 tab leading whitespace before 'struct evp_pkey_ctx_st {'", so maybe "only attach pvclock(4) inside a KVM guest" would've fixed it? Thanks Greg