TITLE: general protection fault in locks_remove_file

[   51.907753] kasan: CONFIG_KASAN_INLINE enabled
[   51.913122] kasan: GPF could be caused by NULL-ptr deref or user memory access
[   51.920573] general protection fault: 0000 [#1] PREEMPT SMP KASAN
[   51.926803] CPU: 1 PID: 5670 Comm: syz-executor439 Not tainted 4.20.0-rc1-next-20181107+ #107
[   51.935630] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   51.944987] RIP: 0010:__x86_indirect_thunk_rbx+0x10/0x20
[   51.950426] Code: 90 0f ae e8 eb f9 48 89 04 24 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 e8 07 00 00 00 f3 90 0f ae e8 eb f9 48 89 1c 24 <c3> 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 e8 07 00 00 00 f3
[   51.969311] RSP: 0018:ffff8801d89af2b0 EFLAGS: 00010293
[   51.974657] RAX: ffff8801d49723c0 RBX: 894cdffffc000000 RCX: ffffffff81ed555d
[   51.981912] RDX: 0000000000000000 RSI: ffffffff81ed5c9e RDI: ffff8801d89af338
[   51.989163] RBP: ffff8801d89af4a0 R08: ffff8801d49723c0 R09: ffffed003b5e5b67
[   51.996423] R10: ffffed003b5e5b67 R11: ffff8801daf2db3b R12: ffff8801d798da00
[   52.003684] R13: ffff8801d89af338 R14: 1ffff1003b135e5b R15: dffffc0000000000
[   52.010937] FS:  0000000001292880(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
[   52.019142] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   52.025108] CR2: 0000000020e2aff8 CR3: 000000000946a000 CR4: 00000000001406e0
[   52.032381] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   52.039643] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   52.047009] Call Trace:
[   52.095282]  locks_remove_file+0x148/0x5c0
[   52.125426]  __fput+0x2f0/0xa70
[   52.150364]  ____fput+0x15/0x20
[   52.153639]  task_work_run+0x1e8/0x2a0
[   52.172015]  do_exit+0x1ad1/0x26d0
[   52.338992]  do_group_exit+0x177/0x440
[   52.356309]  __x64_sys_exit_group+0x3e/0x50
[   52.360613]  do_syscall_64+0x1b9/0x820
[   52.397610]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   52.402783] RIP: 0033:0x43ec48
[   52.405975] Code: Bad RIP value.
[   52.409321] RSP: 002b:00007fff104a8308 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
[   52.417010] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ec48
[   52.424344] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
[   52.431710] RBP: 00000000004be508 R08: 00000000000000e7 R09: ffffffffffffffd0
[   52.438977] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
[   52.446237] R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000
[   52.453585] Modules linked in:
[   52.457384] ---[ end trace db9bef1a2174e463 ]---
[   52.462348] RIP: 0010:__x86_indirect_thunk_rbx+0x10/0x20
[   52.467786] Code: 90 0f ae e8 eb f9 48 89 04 24 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 e8 07 00 00 00 f3 90 0f ae e8 eb f9 48 89 1c 24 <c3> 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 e8 07 00 00 00 f3
[   52.486966] RSP: 0018:ffff8801d89af2b0 EFLAGS: 00010293
[   52.492409] RAX: ffff8801d49723c0 RBX: 894cdffffc000000 RCX: ffffffff81ed555d
[   52.499674] RDX: 0000000000000000 RSI: ffffffff81ed5c9e RDI: ffff8801d89af338
[   52.506997] RBP: ffff8801d89af4a0 R08: ffff8801d49723c0 R09: ffffed003b5e5b67
[   52.514416] R10: ffffed003b5e5b67 R11: ffff8801daf2db3b R12: ffff8801d798da00
[   52.521806] R13: ffff8801d89af338 R14: 1ffff1003b135e5b R15: dffffc0000000000
[   52.529078] FS:  0000000001292880(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
[   52.537347] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   52.543267] CR2: 000000000043ec1e CR3: 000000000946a000 CR4: 00000000001406e0
[   52.550560] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   52.557825] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   52.565138] Kernel panic - not syncing: Fatal exception
[   52.571795] Kernel Offset: disabled
[   52.575422] Rebooting in 86400 seconds..