Fatal trap 9: general protection fault while in kernel mode
cpuid = 5; lapic id = 5
instruction pointer	= 0x8:0xffffffff80bd4c48
stack pointer	        = 0x10:0xfffff80117f77890
frame pointer	        = 0x10:0xfffff80117f778c8
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 0, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 853
current thread          = pri 6 (CRIT)
kernel: type 9 trap, code=0

CPU5 stopping CPUs: 0x0000001f
 stopped
Stopped at      set_user_TLS+0x68:      wrmsr
db>

[RIP 0xffffffff80bd4c48 identified via objdump -d /boot/kernel/kernel:
 ffffffff80bd4c3f: b9 00 01 00 c0  mov $0xc0000100,%ecx   <- MSR_FSBASE
 ffffffff80bd4c44: 48 c1 ea 20     shr $0x20,%rdx
 ffffffff80bd4c48: 0f 30           wrmsr                  <- #GP(0)]

[Earlier discovery run, different boot, matrix harness tls_edge.c:
 Fatal trap 9 ... current process = 922 ... Stopped at set_user_TLS+0x68: wrmsr
 preceded by "pid 898 (tls_edge), uid 65534: exited on signal 11" from the
 pre-fix matrix (user-mode #GP from the same wild base after QEMU-accepted
 install in a different harness instance).]