login: [  27.5844818] panic: kernel diagnostic assertion "vp->v_usecount != 0" failed: file "/syzkaller/managers/netbsd/kernel/sys/kern/vfs_vnode.c", line 869 
[  27.5844818] cpu1: Begin traceback...
[  27.5956115] vpanic() at netbsd:vpanic+0x214
[  27.5956115] _GLOBAL__sub_D_65535_0_cpu_configure() at netbsd:_GLOBAL__sub_D_65535_0_cpu_configure
[  27.6067348] vref() at netbsd:vref+0x54
[  27.6178633] getcwd_common() at netbsd:getcwd_common+0x10d
[  27.6289882] vn_isunder() at netbsd:vn_isunder+0x1e
[  27.6401146] lookup_once() at netbsd:lookup_once+0x252
[  27.6623673] namei_tryemulroot() at netbsd:namei_tryemulroot+0x613
[  27.6734922] namei() at netbsd:namei+0x65
[  27.6846185] vn_open() at netbsd:vn_open+0x12d
[  27.6957447] do_open() at netbsd:do_open+0x228
[  27.7068709] do_sys_openat() at netbsd:do_sys_openat+0x130
[  27.7179973] sys_openat() at netbsd:sys_openat+0xc0
[  27.7291238] sys_syscall() at netbsd:sys_syscall+0xe2
[  27.7402494] syscall() at netbsd:syscall+0x30e
[  27.7513750] --- syscall (number 0) ---
[  27.7513750] 7e4a5d03f4ca:
[  27.7513750] cpu1: End traceback...

[  27.7625016] dumping to dev 4,1 (offset=0, size=0): not possible
[  27.7625016] rebooting...
SeaBIOS (version 1.8.2-20190204_181744-google)
Total RAM Size = 0x00000001e0000000 = 7680 MiB
CPUs found: 2     Max CPUs supported: 2
found virtio-scsi at 0:3
virtio-scsi vendor='Google' product='PersistentDisk' rev='1' type=0 removable=0
virtio-scsi blksize=512 sectors=4194304 = 2048 MiB
drive 0x000f2a00: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304
Booting from Hard Disk 0...

>> NetBSD/x86 BIOS Boot, Revision 5.10 (Tue Jul 17 14:59:51 UTC 2018) (from NetBSD 8.0)
>> Memory: 639/3144640 k

     1. Boot normally
     2. Boot single user
     3. Disable ACPI
     4. Disable ACPI and SMP
     5. Drop to boot prompt