------------[ cut here ]------------
kernel BUG at lib/list_debug.c:53!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 8992 Comm: syz-executor5 Not tainted 4.13.0-rc5-next-20170817+ #5
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88003c5a64c0 task.stack: ffff880036238000
RIP: 0010:__list_del_entry_valid+0xef/0x150 lib/list_debug.c:51
RSP: 0018:ffff88003623eef8 EFLAGS: 00010282
RAX: 0000000000000054 RBX: ffff880039e97a80 RCX: 0000000000000000
RDX: 0000000000000054 RSI: ffffffff81582c0e RDI: ffffed0006c47dd3
RBP: ffff88003623ef10 R08: 0000000000000000 R09: 1ffff10006c47d71
R10: ffff88003623edd8 R11: ffffffff85b2cbf8 R12: ffff880039e97a80
R13: dffffc0000000000 R14: ffff88003e306e00 R15: ffff88003623f140
FS:  00007f1eccdaf700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001ddbc21000 CR3: 000000003b03d000 CR4: 00000000000026f0
Call Trace:
 __list_del_entry include/linux/list.h:116 [inline]
 list_del include/linux/list.h:124 [inline]
 __remove_wait_queue include/linux/wait.h:182 [inline]
 userfaultfd_event_wait_completion+0x519/0x910 fs/userfaultfd.c:573
 dup_fctx fs/userfaultfd.c:669 [inline]
 dup_userfaultfd_complete+0x2de/0x480 fs/userfaultfd.c:677
 dup_mmap kernel/fork.c:719 [inline]
 dup_mm kernel/fork.c:1178 [inline]
 copy_mm+0xde2/0x1247 kernel/fork.c:1232
 copy_process.part.36+0x1ea3/0x4af0 kernel/fork.c:1734
 copy_process kernel/fork.c:1547 [inline]
 _do_fork+0x1ef/0xfb0 kernel/fork.c:2026
 SYSC_clone kernel/fork.c:2136 [inline]
 SyS_clone+0x37/0x50 kernel/fork.c:2130
 do_syscall_64+0x26c/0x8c0 arch/x86/entry/common.c:287
 entry_SYSCALL64_slow_path+0x25/0x25
RIP: 0033:0x446749
RSP: 002b:00007f1eccdaec08 EFLAGS: 00000286 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000446749
RDX: 0000000020f42000 RSI: 0000000020179000 RDI: 0000000000000000
RBP: 0000000000708000 R08: 0000000020ef4ffc R09: 0000000000000000
R10: 0000000020a6bffc R11: 0000000000000286 R12: 00000000ffffffff
R13: 00000000000003b0 R14: 00000000006e2470 R15: 0000000020179000
Code: 4c 89 e2 48 c7 c7 a0 a9 fd 84 e8 12 5f 1b ff 0f 0b 48 c7 c7 00 aa fd 84 e8 04 5f 1b ff 0f 0b 48 c7 c7 60 aa fd 84 e8 f6 5e 1b ff <0f> 0b 48 c7 c7 c0 aa fd 84 e8 e8 5e 1b ff 0f 0b 48 89 df 48 89 
RIP: __list_del_entry_valid+0xef/0x150 lib/list_debug.c:51 RSP: ffff88003623eef8
---[ end trace 28c8424cdcf5c57c ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..