r348750 amd64 panic: bad pte va 8002de000 pte 8002de000

One of remote systems got this panic.
Unfortunately, all I have is this bit of its console log.
No crash dump (not even a text dump).
It's curious that va == pte.

panic: bad pte va 8002de000 pte 8002de000^M
cpuid = 0^M
time = 1561459522^M
KDB: stack backtrace:^M
db_trace_self_wrapper() at 0xffffffff804f128b = db_trace_self_wrapper+0x2b/frame
0xfffffe00aa88b6c0^M
kdb_backtrace() at 0xffffffff8072c379 = kdb_backtrace+0x39/frame
0xfffffe00aa88b770^M
vpanic() at 0xffffffff806ed08c = vpanic+0x19c/frame 0xfffffe00aa88b7c0^M
panic() at 0xffffffff806ecc83 = panic+0x43/frame 0xfffffe00aa88b820^M
pmap_remove_pages() at 0xffffffff809b40b4 = pmap_remove_pages+0x6f4/frame
0xfffffe00aa88b910^M
vmspace_exit() at 0xffffffff809774bf = vmspace_exit+0xbf/frame 0xfffffe00aa88b960^M
exit1() at 0xffffffff806b083b = exit1+0x5ab/frame 0xfffffe00aa88b9c0^M
sys_sys_exit() at 0xffffffff806b028d = sys_sys_exit+0xd/frame 0xfffffe00aa88b9d0^M
syscallenter() at 0xffffffff809c17e1 = syscallenter+0x251/frame 0xfffffe00aa88ba10^M
amd64_syscall() at 0xffffffff809c13d7 = amd64_syscall+0x17/frame
0xfffffe00aa88bab0^M
fast_syscall_common() at 0xffffffff809a00cd = fast_syscall_common+0x101/frame
0xfffffe00aa88bab0^M
--- syscall (1, FreeBSD ELF64, sys_sys_exit), rip = 0x8003edf1a, rsp =
0x7fffffffd828, rbp = 0x7fffffffd910 ---^M

-- 
Andriy Gapon