In case this is interesting. I'm not sure if I can reproduce it yet
acpibut0: power button pressed, shutting down! syncing disks... 4 done unmounted /dev/sd2a on /mnt type msdos unmounted tmpfs on /var/shm type tmpfs unmounted procfs on /proc type procfs unmounted kernfs on /kern type kernfs sd0: detached scsibus0: detached cd0: detached atapibus0: detached audio0: detached atabus1: detached pci6: detached pci5: detached pci2: detached sysbeep0: detached midi0: detached ppb5: detached ppb4: detached ppb1: detached audio1: detached forcefully unmounted ptyfs on /dev/pts type ptyfs forcefully unmounted tmpfs on /tmp type tmpfs Skipping crash dump on recursive panic panic: kernel diagnostic assertion "offset != 0 && offset < softint_bytes" failed: file "/usr/src/sys/kern/kern_softint.c", line 484 0 8192 cpu0: Begin traceback... vpanic() at netbsd:vpanic+0x140 cd_play_msf() at netbsd:cd_play_msf softint_schedule() at netbsd:softint_schedule+0x7e audio_pint() at netbsd:audio_pint+0x39e hdafg_stream_intr() at netbsd:hdafg_stream_intr+0xc2 hdaudio_intr() at netbsd:hdaudio_intr+0x9e Xintr_ioapic_level4() at netbsd:Xintr_ioapic_level4+0xf2 --- interrupt --- x86_pause() at netbsd:x86_pause+0x2 sleepq_block() at netbsd:sleepq_block+0x1c5 cv_timedwait_sig() at netbsd:cv_timedwait_sig+0x107 ttysleep() at netbsd:ttysleep+0x7c ttread() at netbsd:ttread+0x296 cdev_read() at netbsd:cdev_read+0x70 spec_read() at netbsd:spec_read+0xc3 VOP_READ() at netbsd:VOP_READ+0x37 vn_read() at netbsd:vn_read+0x94 dofileread() at netbsd:dofileread+0x8f sys_read() at netbsd:sys_read+0x5f syscall() at netbsd:syscall+0x15b --- syscall (number 3) --- 7db7c203da7a: cpu0: End traceback... rebooting... Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 The NetBSD Foundation, Inc. All rights reserved. Copyright (c) 1982, 1986, 1989, 1991, 1993 The Regents of the University of California. All rights reserved. ..