Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address	= 0x30
fault code		= supervisor read data, page not present
instruction pointer	= 0x20:0xffffffff81539d5a
stack pointer	        = 0x28:0xfffffe0020ef97a0
frame pointer	        = 0x28:0xfffffe0020ef97e0
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 69736 (syz-executor.2)
trap number		= 12
panic: page fault
cpuid = 1
time = 5
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe0020ef9400
vpanic() at vpanic+0x1e0/frame 0xfffffe0020ef9460
panic() at panic+0x43/frame 0xfffffe0020ef94c0
trap_fatal() at trap_fatal+0x4de/frame 0xfffffe0020ef9540
trap_pfault() at trap_pfault+0x9f/frame 0xfffffe0020ef95b0
trap() at trap+0x44d/frame 0xfffffe0020ef96d0
calltrap() at calltrap+0x8/frame 0xfffffe0020ef96d0
--- trap 0xc, rip = 0xffffffff81539d5a, rsp = 0xfffffe0020ef97a0, rbp = 0xfffffe0020ef97e0 ---
vm_page_unhold_pages() at vm_page_unhold_pages+0x5a/frame 0xfffffe0020ef97e0
pipe_write() at pipe_write+0x16d8/frame 0xfffffe0020ef98b0
dofilewrite() at dofilewrite+0xfd/frame 0xfffffe0020ef9910
kern_writev() at kern_writev+0x66/frame 0xfffffe0020ef9950
sys_writev() at sys_writev+0x50/frame 0xfffffe0020ef9980
amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe0020ef9ab0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe0020ef9ab0
--- syscall (198, FreeBSD ELF64, nosys), rip = 0x4131fa, rsp = 0x7fffdfffdf38, rbp = 0x3 ---
KDB: enter: panic
[ thread pid 69736 tid 100304 ]
Stopped at      kdb_enter+0x6a: movq    $0,kdb_why