kern/53993: panic on wrmsr in cpu_switchto

[fstd.lkml%gmail.com@localhost]

>Number:         53993
>Category:       kern
>Synopsis:       panic on wrmsr in cpu_switchto
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Feb 19 17:15:00 +0000 2019
>Originator:     Timo Buhrmester
>Release:        8-stable
>Organization:
>Environment:
NetBSD lemon.pr0.tips 8.0_STABLE NetBSD 8.0_STABLE (LEMONKERND) #0: Mon Feb 18 00:16:18 CET 2019  build%kiwi.pr0.tips@localhost:/stor/netbsd/foreign/lemon-apu/obj/sys/arch/amd64/compile/LEMONKERND amd64
>Description:
I'm running 8-stable on this (mostly open) hardware: https://www.pcengines.ch/apu2c4.htm.

Every so many days, I'm getting this panic:

| fatal protection fault in supervisor mode
| trap type 4 code 0 rip 0xffffffff80208653 cs 0x8 rflags 0x10246 cr2 0x7f7fff97c328 ilevel 0x8 rsp 0xffff800068235a20
| curlwp 0xfffffe810e4df8c0 pid 13063.1 lowest kstack 0xffff8000682322c0
| kernel: protection fault trap, code=0
| Stopped in pid 13063.1 (grep) at        netbsd:cpu_switchto+0x153:      wrmsr
| db{0}> bt
| cpu_switchto() at netbsd:cpu_switchto+0x153
| kpreempt() at netbsd:kpreempt+0xe0
| DDB lost frame for netbsd:Xresume_preempt+0x28, trying 0xffff800068235af0
| Xresume_preempt() at netbsd:Xresume_preempt+0x28
| --- interrupt ---
| ?() at 206
| allproc() at ffffffff814c4240
| ?() at fffffe81079b92d0
| Bad frame pointer: 0xfffffe8107dcf2d8
| db{0}> show registers
| ds          92d0
| es          babb
| fs          59f0
| gs          babb
| rdi         fffffe81079b92d0
| rsi         fffffe810e4df8c0
| rbp         ffff800068235ab0
| rbx         fffffe81079ae1e0
| rdx         f8cff33d
| rcx         c0000102
| rax         9044ffff
| r8          ffffffff81400600    cpu_info_primary
| r9          fffffe811ea1a044
| r10         400
| r11         fffffe8107401048
| r12         fffffe810e4df8c0
| r13         fffffe81079ae1e0
| r14         ffff800068232000
| r15         fffffe811ea1ef40
| rip         ffffffff80208653    cpu_switchto+0x153
| cs          8 
| rflags      10246
| rsp         ffff800068235a20
| ss          0 
| netbsd:cpu_switchto+0x153:      wrmsr

Does this ring a bell for anybody?  Does it look like it might rather be a hardware issue?

>How-To-Repeat:

>Fix: