page:ffffea00071f0000 count:2 mapcount:0 mapping:          (null) index:0x0
flags: 0x8000000000004004(referenced|head)
page dumped because: VM_BUG_ON_PAGE(!PageLocked(page))
------------[ cut here ]------------
kernel BUG at mm/filemap.c:817!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 8949 Comm: syz-executor4 Not tainted 4.4.150-g5541782 #19
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800b67ac800 task.stack: ffff8800a4ec0000
RIP: 0010:[<ffffffff81421375>]  [<ffffffff81421375>] unlock_page+0x115/0x150 mm/filemap.c:817
RSP: 0018:ffff8800a4ec7828  EFLAGS: 00010216
RAX: ffffffff83a6f940 RBX: ffffea00071f0000 RCX: ffffc90008076000
RDX: 000000000001f472 RSI: ffffffff815184c9 RDI: ffff8800b67ad0dc
RBP: ffff8800a4ec7848 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
R13: ffffea00071f0300 R14: ffffea00071f0008 R15: ffff8800a4ec7910
FS:  0000000000000000(0000) GS:ffff8801db300000(0063) knlGS:00000000f5759b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000020048000 CR3: 00000000b5d3e000 CR4: 00000000001606f0
Stack:
 ffffea00071f0000 dffffc0000000000 ffffea00071f0300 ffffea00071f0008
 ffff8800a4ec7938 ffffffff812cf1ad 0000000000000000 ffff8800a4ec7a80
 ffff8800b6f10000 1ffff100149d8f16 00000001aecec8b0 ffff8800a4ec7a70
Call Trace:
 [<ffffffff812cf1ad>] get_futex_key+0x8ad/0xdc0 kernel/futex.c:598
 [<ffffffff812d0e67>] futex_requeue+0x1e7/0x1690 kernel/futex.c:1780
 [<ffffffff812d3974>] do_futex+0x204/0x17f0 kernel/futex.c:3248
 [<ffffffff812d5a69>] C_SYSC_futex kernel/futex_compat.c:200 [inline]
 [<ffffffff812d5a69>] compat_SyS_futex+0x1d9/0x2f0 kernel/futex_compat.c:174
 [<ffffffff81006d94>] do_syscall_32_irqs_on arch/x86/entry/common.c:393 [inline]
 [<ffffffff81006d94>] do_fast_syscall_32+0x324/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff838cca03>] sysenter_flags_fixed+0xd/0x1a
Code: e8 48 8d 04 c0 49 [  171.958886] SELinux: unrecognized netlink message: protocol=0 nlmsg_type=44776 sclass=netlink_route_socket
8d 3c c6 e8 b8 bc df ff 5b 41 5c 41 5d 41 5e 5d c3 e8 7a 31 f3 ff 48 c7 c6 e0 bb a9 83 48 89 df e8 bb ee 06 00 <0f> 0b 48 89 df e8 11 c9 0d 00 e9 0a ff ff ff e8 07 c9 0d 00 e9 
RIP  [<ffffffff81421375>] unlock_page+0x115/0x150 mm/filemap.c:817
 RSP <ffff8800a4ec7828>
---[ end trace 91ff19201e68e275 ]---