The last few days I am getting repeated panics on amd64 -current running under VirtualBox (latest 5.1.14 version at the moment) as follows:
panic: auidui_init_ringbuffer: blksize=0
fatal breakpoint trap in supervisor mode
trap type 1 code 0 rip ffffffff80115455 cs 8 rflags 246 cr2 0 ilevel 8 rsp fffffe8043d4bf80
curlwp 0xfffffe8043d54620 pid 0.45 lowest kstack 0xfffffe8043d492c0
Stopped in pid 0.45 (system) at netbsd:breakpoint+0x5: leave
db{2}> bt
breakpoint() at netbsd:breakpoint+0x5
vpanic() at netbsd:vpanic+0x140
snprintf() at netbsd:snprintf
audio_initbufs() at netbsd:audio_initbufs
audio_initbufs() at netbsd:audio_initbufs+0xb4
audiosetinfo() at netbsd:audiosetinfo+0x95e
audio_set_vchan_defaults.isra.14.constprop.16() at netbsd:audio_set_vchan_defaults.isra.14.constprop.16+0x17b
audioattach() at netbsd:audioattach+0x68a
config_attach_loc() at netbsd:config_attach_loc+0x17a
config_found_sm_loc() at netbsd:config_found_sm_loc+0x48
audio_attach_mi() at netbsd:audio_attach_mi+0x32
auich_finish_attach() at netbsd:auich_finish_attach+0x4e
config_interrupts_thread() at netbsd:config_interrupts_thread+0x30
db{2}>
The dmesg buffer is not saved and for some reason 'reboot 0x104' does not produce a dump, so the above is manually taken.