page:ffffea0007228000 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: 19678 Comm: syz-executor7 Not tainted 4.4.153-g5e24b4e #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801c9ca3000 task.stack: ffff8800a5be8000
RIP: 0010:[<ffffffff81421415>]  [<ffffffff81421415>] unlock_page+0x115/0x150 mm/filemap.c:817
RSP: 0018:ffff8800a5bef4b0  EFLAGS: 00010293
RAX: ffffffff83a6f940 RBX: ffffea0007228000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815195a9 RDI: ffff8801c9ca38dc
RBP: ffff8800a5bef4d0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
R13: ffffea0007228040 R14: ffffea0007228008 R15: ffff8800a5bef598
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000020400000 CR3: 00000000b7647000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffea0007228000 dffffc0000000000 ffffea0007228040 ffffea0007228008
 ffff8800a5bef5c0 ffffffff812cf25d ffff8800a5bef688 ffff8800a5bef638
 ffff8800b76b6800 1ffff10014b7dea7 00000001c9ca38d8 ffff8800a5bef628
Call Trace:
 [<ffffffff812cf25d>] get_futex_key+0x8ad/0xdc0 kernel/futex.c:598
 [<ffffffff812cf865>] futex_wake+0xf5/0x460 kernel/futex.c:1419
 [<ffffffff812d3a8d>] do_futex+0x26d/0x17f0 kernel/futex.c:3230
 [<ffffffff812d5200>] SYSC_futex kernel/futex.c:3286 [inline]
 [<ffffffff812d5200>] SyS_futex+0x1f0/0x300 kernel/futex.c:3254
 [<ffffffff8112a591>] mm_release+0x2d1/0x400 kernel/fork.c:953
 [<ffffffff81137cd0>] exit_mm kernel/exit.c:395 [inline]
 [<ffffffff81137cd0>] do_exit+0x3b0/0x26b0 kernel/exit.c:742
 [<ffffffff8113e241>] do_group_exit+0x111/0x330 kernel/exit.c:885
 [<ffffffff8116163c>] get_signal+0x4ec/0x14b0 kernel/signal.c:2321
 [<ffffffff8100df4b>] do_signal+0x8b/0x1d30 arch/x86/kernel/signal.c:712
 [<ffffffff8100360a>] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:249
 [<ffffffff8100708e>] prepare_exit_to_usermode arch/x86/entry/common.c:284 [inline]
 [<ffffffff8100708e>] syscall_return_slowpath arch/x86/entry/common.c:349 [inline]
 [<ffffffff8100708e>] do_syscall_32_irqs_on arch/x86/entry/common.c:399 [inline]
 [<ffffffff8100708e>] do_fast_syscall_32+0x61e/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff838ce1c3>] sysenter_flags_fixed+0xd/0x1a
Code: e8 48 8d 04 c0 49 8d 3c c6 e8 88 bd df ff 5b 41 5c 41 5d 41 5e 5d c3 e8 8a 31 f3 ff 48 c7 c6 e0 bb a9 83 48 89 df e8 bb ee 06 00 <0f> 0b 48 89 df e8 51 d3 0d 00 e9 0a ff ff ff e8 47 d3 0d 00 e9 
RIP  [<ffffffff81421415>] unlock_page+0x115/0x150 mm/filemap.c:817
 RSP <ffff8800a5bef4b0>
---[ end trace 6511ec4f9ea505b5 ]---