syzbot

Fatal trap 9: general protection fault while in kernel mode
cpuid = 0; apic id = 00
instruction pointer	= 0x20:0xffffffff81163cf5
stack pointer	        = 0x28:0xfffffe001fa0e610
frame pointer	        = 0x28:0xfffffe001fa0e650
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		= 907 (syz-executor9083768)
trap number		= 9
panic: general protection fault
cpuid = 0
time = 1552881695
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe001fa0e2e0
vpanic() at vpanic+0x1e0/frame 0xfffffe001fa0e340
panic() at panic+0x43/frame 0xfffffe001fa0e3a0
trap_fatal() at trap_fatal+0x4c6/frame 0xfffffe001fa0e420
trap() at trap+0xba/frame 0xfffffe001fa0e540
calltrap() at calltrap+0x8/frame 0xfffffe001fa0e540
--- trap 0x9, rip = 0xffffffff81163cf5, rsp = 0xfffffe001fa0e610, rbp = 0xfffffe001fa0e650 ---
unp_dispose() at unp_dispose+0xa5/frame 0xfffffe001fa0e650
sofree() at sofree+0x42c/frame 0xfffffe001fa0e6b0
soclose() at soclose+0x5b3/frame 0xfffffe001fa0e730
_fdrop() at _fdrop+0x3a/frame 0xfffffe001fa0e760
closef() at closef+0x27d/frame 0xfffffe001fa0e7f0
fdescfree_fds() at fdescfree_fds+0xbd/frame 0xfffffe001fa0e840
fdescfree() at fdescfree+0x58a/frame 0xfffffe001fa0e900
exit1() at exit1+0x780/frame 0xfffffe001fa0e970
sys_sys_exit() at sys_sys_exit+0xd/frame 0xfffffe001fa0e980
amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe001fa0eab0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe001fa0eab0
--- syscall (1, FreeBSD ELF64, sys_sys_exit), rip = 0x447a0a, rsp = 0x7fffffffea68, rbp = 0x7fffffffea80 ---
KDB: enter: panic
[ thread pid 907 tid 100096 ]
Stopped at      kdb_enter+0x6a: movq    $0,kdb_why
db>