Howdy. Please excuse this poor bug report, I'm not able to obtain more info as the system locks hard (below is transcribed by hand).
On a clean install, with the latest snap (as of time of email): OpenBSD 6.3-current (GENERIC.MP) #207: Wed Apr 18 11:37:15 MDT 2018 CPU: AMD A8-7670K Radeon R7 aka Kaveri extent_free(ffffffff819489f8,100,1000,7e281000) at extent_free+0x110 bus_space_unmap(0,ffff8000000de000,0) at bus_space_unmap+0x110 radeon_device_fini(ffff8000000de000) at radeon_device_fini+0x43 radeondrm_detach_kms(0,ffff8000000de000) at radeondrm_detach_kms+0x33 config_detach(ffff8000000dd600,ffff8000000de000) at config_detach+0x14e radeondrm_attachhook(ffffffff81bf9420) at radeondrm_attachhook+0x9d config_process_deferred_mountroot() at config_process_deferred_mountroot+0x56 main(6dd84e08) at main+0x80f +--+ Carlos
