random: nonblocking pool is initialized
page:ffffea000764ce00 count:4 mapcount:1 mapping:          (null) index:0x0
flags: 0x8000000000004010(dirty|head)
page dumped because: VM_BUG_ON_PAGE(!PageLocked(page))
------------[ cut here ]------------
kernel BUG at mm/filemap.c:819!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 3848 Comm: syzkaller445926 Not tainted 4.4.128-ged3b23f #18
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d2d28000 task.stack: ffff8801d98a8000
RIP: 0010:[<ffffffff8141df45>]  [<ffffffff8141df45>] unlock_page+0x115/0x150 mm/filemap.c:819
RSP: 0018:ffff8801d98af838  EFLAGS: 00010293
RAX: ffffffff83a6e7c0 RBX: ffffea000764ce00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815130e9 RDI: ffff8801d2d288dc
RBP: ffff8801d98af858 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
R13: ffff8801d98afab8 R14: ffffea000764ce40 R15: ffffea000764ce08
FS:  0000000000000000(0000) GS:ffff8801db300000(0063) knlGS:0000000009503840
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000002029a000 CR3: 00000001d9240000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffea000764ce00 dffffc0000000000 ffff8801d98afab8 ffffea000764ce40
 ffff8801d98af940 ffffffff812cc19c 00000000ffeabb00 ffff8801d98af888
 ffffffff812e8f6a ffff8800b1668f00 00000000d98af8a0 ffff8801d98afac8
Call Trace:
 [<ffffffff812cc19c>] get_futex_key+0xadc/0xd80 kernel/futex.c:598
 [<ffffffff812cdc0c>] futex_requeue+0x20c/0x1690 kernel/futex.c:1743
 [<ffffffff812d06f2>] do_futex+0x202/0x1770 kernel/futex.c:3208
 [<ffffffff812d2769>] C_SYSC_futex kernel/futex_compat.c:200 [inline]
 [<ffffffff812d2769>] compat_SyS_futex+0x1d9/0x2f0 kernel/futex_compat.c:174
 [<ffffffff81006d96>] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline]
 [<ffffffff81006d96>] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:459
 [<ffffffff838c00aa>] sysenter_flags_fixed+0xd/0x17
Code: e8 48 8d 04 c0 49 8d 3c c6 e8 f8 be df ff 5b 41 5c 41 5d 41 5e 5d c3 e8 8a 32 f3 ff 48 c7 c6 60 aa a9 83 48 89 df e8 4b eb 06 00 <0f> 0b 48 89 df e8 61 af 0d 00 e9 0a ff ff ff e8 57 af 0d 00 e9 
RIP  [<ffffffff8141df45>] unlock_page+0x115/0x150 mm/filemap.c:819
 RSP <ffff8801d98af838>
---[ end trace eaf69739bdde8b55 ]---