[  86.7874086] panic: kernel diagnostic assertion "to_ticks >= 0" failed: file "/syzkaller/managers/netbsd/kernel/sys/kern/kern_timeout.c", line 335 
[  86.7974254] cpu1: Begin traceback...
[  86.8074438] vpanic() at netbsd:vpanic+0x214
[  86.8174602] _GLOBAL__sub_D_65535_0_cpu_configure() at netbsd:_GLOBAL__sub_D_65535_0_cpu_configure
[  86.8274753] callout_schedule_locked() at netbsd:callout_schedule_locked+0x25b
[  86.8374940] sleepq_block() at netbsd:sleepq_block+0x2e9
[  86.8475120] cv_timedwait_sig() at netbsd:cv_timedwait_sig+0x16f
[  86.8575283] sbwait() at netbsd:sbwait+0xa2
[  86.8675443] soreceive() at netbsd:soreceive+0x14ec
[  86.8775604] do_filereadv() at netbsd:do_filereadv+0x42e
[  86.8875775] sys___syscall() at netbsd:sys___syscall+0xe2
[  86.9076140] syscall() at netbsd:syscall+0x32e
[  86.9076140] --- syscall (number 198) ---
[  86.9176288] 792a97a3f4aa:
[  86.9176288] cpu1: End traceback...

[  86.9176288] dumping to dev 4,1 (offset=0, size=0): not possible
[  86.9276454] rebooting...
SeaBIOS (version 1.8.2-20190322_093631-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 0x000f29c0: 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