Today I'm suddenly unable to boot a newly built kernel without crashing right near the end of the device probes, just before the system is about to actually come up:

Fatal trap 18: integer divide fault while in kernel mode

Stopped at 0xffffffff803b2646 = g_label_ufs_taste_common+0x36 divl 0x50(%rcx),%eax

Backtrace lists this chain of calls: g_label_ufs_taste_common g_label_taste g_new_provider_event g_run_events g_event_procbody fork_exit fork_trampoline

Whether built with clang or gcc, CUSTOM config or GENERIC, same results on rebooting. No idea why this suddenly started happening, haven't changed anything at all in my setup.