panic: pmap_demote_pde: page table page for a wired mapping is missing
cpuid = 1
time = 1553103264
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe00212846b0
vpanic() at vpanic+0x1e0/frame 0xfffffe0021284710
panic() at panic+0x43/frame 0xfffffe0021284770
pmap_demote_pde_locked() at pmap_demote_pde_locked+0x1288/frame 0xfffffe0021284840
pmap_remove() at pmap_remove+0x5c8/frame 0xfffffe00212848d0
vm_map_protect() at vm_map_protect+0x666/frame 0xfffffe0021284940
sys_mprotect() at sys_mprotect+0xcc/frame 0xfffffe0021284980
amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe0021284ab0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe0021284ab0
--- syscall (198, FreeBSD ELF64, nosys), rip = 0x412e5a, rsp = 0x7fffdfffdf38, rbp = 0x3 ---
KDB: enter: panic
[ thread pid 771 tid 100119 ]
Stopped at      kdb_enter+0x6a: movq    $0,kdb_why