Xen Domu kernel crash at start of boot

[Chuck Zmudzinski <frchuckz%gmail.com@localhost>]

I am getting a kernel crash almost immediately after booting the current 
kernel. I am running NetBSD/xen amd64 on a Debian Linux 8.10 DOM0 which 
uses Xen-4.4. Last week's kernel was good. I built a kernel from a cvs 
update a couple of days ago and tried it. It crashed. I tried the most 
recent daily snapshot available from NetBSD daily builds. It crashed 
too. Here is the information from the console about the daily snapshot 
kernel that crashed (it was built earlier today):

[   1.0000000] NetBSD 8.99.19 (XEN3_DOMU) #0: Thu Jun 21 11:48:05 UTC 2018
[   1.0000000] 
mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/xen/compile/XEN3_DOMU

Here is the information I got from the console about the crash:

[   1.0000000] total memory = 3072 MB
[   1.0000000] avail memory = 2963 MB
[   1.0000000] cpu_rng: RDRAND
[   1.0000000] running cgd selftest aes-xts-256 aes-xts-512 done
[   1.0000000] mainbus0 (root)
[   1.0000000] hypervisor0 at mainbus0: Xen version 4.4.1
[   1.0000000] vcpu0 at hypervisor0
[   1.0000000] vcpu0: Intel(R) Core(TM) i5-4590S CPU @ 3.00GHz, id 0x306c3
[   1.0000000] vcpu0: package 0, core 3, smt 0
[   1.0000000] vcpu1 at hypervisor0
[   1.0000000] vcpu1: Intel(R) Core(TM) i5-4590S CPU @ 3.00GHz, id 0x306c3
[   1.0000000] vcpu1: package 0, core 3, smt 0
[   1.0000000] xenbus0 at hypervisor0: Xen Virtual Bus Interface
[   1.0000000] xencons0 at hypervisor0: Xen Virtual Console Driver
[   1.0000030] fatal protection fault in supervisor mode
[   1.0000030] trap type 4 code 0 rip 0xffffffff80205968 cs 0x10000e030 
rflags 0x10046 cr2 0 ilevel 0 rsp 0xffffa000a570fbf0
[   1.0000030] curlwp 0xffffa0000642d4a0 pid 0.15 lowest kstack 
0xffffa000a570b2c0
kernel: protection fault trap, code=0
Stopped in pid 0.15 (system) at ffffffff80205968:       fxsavel
ds          0
es          0
fs          fd00
gs          0
rdi         ffffa000a570fbf8
rsi         1
rbp         ffffa000a570fe68
rbx         0
rdx         2
rcx         0
rax         0
r8          ffffa00006680000
r9          cccccccccccccccd
r10         64
r11         0
r12         ffffa000a570fbf8
r13         1
r14         0
r15         0
rip         ffffffff80205968
cs          e030
rflags      10046
rsp         ffffa000a570fbf0
ss          e02b
ffffffff80205968:       fxsavel
db{1}> bt
?() at ffffffff80205968
?() at ffffffff802313f0
?() at ffffffff8023155e

I could not get any useful info from addr2line. Any ideas why it crashes?

Thanks,

Chuck Zmudzinski