Core was generated by `kernel.debug'.
Program terminated with signal 4, Illegal instruction.
#0  0x000000000071e75e in _get_mycpu () at ./machine/thread.h:77
77	    __asm ("movq %%gs:globaldata,%0" : "=r" (gd) : "m"(__mycpu__dummy));
#0  0x000000000071e75e in _get_mycpu () at ./machine/thread.h:77
#1  kern_trap (frame=0xb) at /usr/src/sys/platform/vkernel64/x86_64/trap.c:585
#2  0x000000000071fd3a in exc_segfault (signo=<optimized out>, info=<optimized out>, ctxp=<optimized out>) at /usr/src/sys/platform/vkernel64/x86_64/exception.c:269
#3  0x00007fffffdfe003 in ?? ()
#4  0x000000000071fd10 in ?? () at /sys/sys/errno.h:58
#5  0x0000000000000000 in ?? ()
  Id   Target Id         Frame
  4    process 4         0x000000001004d8bc in _umtx_sleep_err () from /usr/lib/libpthread.so.0
  3    process 2         0x00000000102e42dc in umtx_sleep () from /lib/libc.so.8
  2    process 1         0x00000000102e42dc in umtx_sleep () from /lib/libc.so.8
* 1    process 3         0x000000000071e75e in _get_mycpu () at ./machine/thread.h:77

# (fault1.core: identical backtrace - signal 4 (SIGILL), crashing thread
#  = process 3 = first cothread (start=cothread_thread, created under
#  cpu_mask_all_signals); vCPU threads 1 and 2 parked in umtx_sleep
#  inside cpu_idle, never aware the vkernel died.)
# Reconstructed verbatim from the session transcript after guest reset;
# cores were 13 MB each and were not archived.