RDX: 00000000200002c0 RSI: 0000000020000140 RDI: 0000000020000180
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1aa34226d4
R13: 00000000004c2b0c R14: 00000000004d4180 R15: 0000000000000003
==================================================================
BUG: KASAN: stack-out-of-bounds in locks_remove_flock+0x33c/0x350 fs/locks.c:2567
Read of size 8 at addr ffff880185817698 by task syz-executor4/13838

CPU: 0 PID: 13838 Comm: syz-executor4 Not tainted 4.20.0-rc1-next-20181107+ #107
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 locks_remove_flock+0x33c/0x350 fs/locks.c:2567
 locks_remove_file+0x148/0x5c0 fs/locks.c:2607
 __fput+0x2f0/0xa70 fs/file_table.c:271
 ____fput+0x15/0x20 fs/file_table.c:312
 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
 get_signal+0x1550/0x1970 kernel/signal.c:2347
 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816
 exit_to_usermode_loop+0x2e5/0x380 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f5585e2cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000049
RAX: fffffffffffffe00 RBX: 0000000000000002 RCX: 0000000000457569
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000005
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5585e2d6d4
R13: 00000000004bdd9e R14: 00000000004ccdb8 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea00061605c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 ffffffff06160101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff880185817580: f2 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff880185817600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff880185817680: 00 00 f2 f2 f2 00 00 00 00 00 00 00 00 00 00 00
                            ^
 ffff880185817700: 00 00 00 f1 f1 f1 f1 00 00 f2 f2 f2 f2 f2 f2 f8
 ffff880185817780: f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 00 00 00 00 00
==================================================================