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 = 0x20:0xffffffff8156fb9a stack pointer = 0x28:0xfffffe00212317a0 frame pointer = 0x28:0xfffffe00212317e0 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 = 759 (syz-executor3275658) trap number = 12 panic: page fault cpuid = 1 time = 1555564616 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe0021231400 vpanic() at vpanic+0x1e0/frame 0xfffffe0021231460 panic() at panic+0x43/frame 0xfffffe00212314c0 trap_fatal() at trap_fatal+0x4c6/frame 0xfffffe0021231540 trap_pfault() at trap_pfault+0x9f/frame 0xfffffe00212315b0 trap() at trap+0x44d/frame 0xfffffe00212316d0 calltrap() at calltrap+0x8/frame 0xfffffe00212316d0 --- trap 0xc, rip = 0xffffffff8156fb9a, rsp = 0xfffffe00212317a0, rbp = 0xfffffe00212317e0 --- vm_page_unhold_pages() at vm_page_unhold_pages+0x5a/frame 0xfffffe00212317e0 pipe_write() at pipe_write+0x16d8/frame 0xfffffe00212318b0 dofilewrite() at dofilewrite+0xfd/frame 0xfffffe0021231910 kern_writev() at kern_writev+0x66/frame 0xfffffe0021231950 sys_writev() at sys_writev+0x50/frame 0xfffffe0021231980 amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe0021231ab0 fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe0021231ab0 --- syscall (0, FreeBSD ELF64, nosys), rip = 0x4575fa, rsp = 0x7fffdfffdf88, rbp = 0x6b5b08 --- KDB: enter: panic [ thread pid 759 tid 100103 ] Stopped at kdb_enter+0x6a: movq $0,kdb_why