Help with crash (13.1/amd64)

Hello.

One of my servers started rebooting every few days (usually in the 
middle of the night) and I'd like to find out why.

I'm trying hard to get a core, but so far I was not able to achieve this.

Meanwhile... usually there's absolutely nothing in the log, but today it 
left me this:

> Dec 23 04:31:20 xxx syslogd: restart
> Dec 23 04:31:20 xxx syslogd: kernel boot file is /boot/kernel/kernel
> Dec 23 04:31:20 xxx kernel: 
> Dec 23 04:31:20 xxx syslogd: last message repeated 1 times
> Dec 23 04:31:20 xxx kernel: Fatal trap 12: page fault while in kernel mode
> Dec 23 04:31:20 xxx kernel: cpuid = 6; apic id = 0a
> Dec 23 04:31:20 xxx kernel: fault virtual address      = 0x8000010
> Dec 23 04:31:20 xxx kernel: fault code         = supervisor write data, page not present
> Dec 23 04:31:20 xxx kernel: instruction pointer        = 0x20:0xffffffff80969088
> Dec 23 04:31:20 xxx kernel: stack pointer              = 0x28:0xfffffe0146fc1c90
> Dec 23 04:31:20 xxx kernel: frame pointer              = 0x28:0xfffffe0146fc1d60
> Dec 23 04:31:20 xxx kernel: code segment               = base 0x0, limit 0xfffff, type 0x1b
> Dec 23 04:31:20 xxx kernel:                    = DPL 0, pres 1, long 1, def32 0, gran 1
> Dec 23 04:31:20 xxx kernel: processor eflags   = interrupt enabled, resume, IOPL = 0
> Dec 23 04:31:20 xxx kernel: current process            = 69739 (sshd)
> Dec 23 04:31:20 xxx kernel: trap number                = 12
> Dec 23 04:31:20 xxx kernel: panic: page fault
> Dec 23 04:31:20 xxx kernel: cpuid = 6
> Dec 23 04:31:20 xxx kernel: time = 1671766191
> Dec 23 04:31:20 xxx kernel: KDB: stack backtrace:
> Dec 23 04:31:20 xxx kernel: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0146fc1a50
> Dec 23 04:31:20 xxx kernel: vpanic() at vpanic+0x17f/frame 0xfffffe0146fc1aa0
> Dec 23 04:31:20 xxx kernel: panic() at panic+0x43/frame 0xfffffe0146fc1b00
> Dec 23 04:31:20 xxx kernel: trap_fatal() at trap_fatal+0x385/frame 0xfffffe0146fc1b60
> Dec 23 04:31:20 xxx kernel: trap_pfault() at trap_pfault+0x4f/frame 0xfffffe0146fc1bc0
> Dec 23 04:31:20 xxx kernel: calltrap() at calltrap+0x8/frame 0xfffffe0146fc1bc0
> Dec 23 04:31:20 xxx kernel: --- trap 0xc, rip = 0xffffffff80969088, rsp = 0xfffffe0146fc1c90, rbp = 0xfffffe0146fc1d60 ---
> Dec 23 04:31:20 xxx kernel: pmap_remove_pages() at pmap_remove_pages+0x418/frame 0xfffffe0146fc1d60
> Dec 23 04:31:20 xxx kernel: vmspace_exit() at vmspace_exit+0x7f/frame 0xfffffe0146fc1d90
> Dec 23 04:31:20 xxx kernel: exit1() at exit1+0x55f/frame 0xfffffe0146fc1df0
> Dec 23 04:31:20 xxx kernel: sys_sys_exit() at sys_sys_exit+0xd/frame 0xfffffe0146fc1e00
> Dec 23 04:31:20 xxx kernel: amd64_syscall() at amd64_syscall+0x103/frame 0xfffffe0146fc1f30
> Dec 23 04:31:20 xxx kernel: fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe0146fc1f30
> Dec 23 04:31:20 xxx kernel: --- syscall (1, FreeBSD ELF64, sys_sys_exit), rip = 0x8016b82da, rsp = 0x7fffffffd0d8, rbp = 0x7fffffffd0f0 ---
> Dec 23 04:31:20 xxx kernel: Uptime: 7d1h22m11s
> Dec 23 04:31:20 xxx kernel: ---<<BOOT>>---
> Dec 23 04:31:20 xxx kernel: Copyright (c) 1992-2021 The FreeBSD Project.
> Dec 23 04:31:20 xxx kernel: Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
> Dec 23 04:31:20 xxx kernel:    The Regents of the University of California. All rights reserved.
> Dec 23 04:31:20 xxx kernel: FreeBSD is a registered trademark of The FreeBSD Foundation.
> Dec 23 04:31:20 xxx kernel: FreeBSD 13.1-RELEASE-p3 releng/netfence_13.1-n250175-0133d0d8859 xxx amd64

Does this suggest anything to anyone?

  bye & Thanks
	av.

P.S.
Yes, I'm under SSH dictonary attack, and yes, I've got it on a non 
standard port, I'm fighting this with fail2ban, and no, they won't get 
at nothing, since password auth is disabled.