syzbot

incfs: Can't find or create .index dir in ./file0
BUG: Dentry ffff8881efb32220{i=0,n=.index}  still in use (1) [unmount of ramfs ramfs]
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WARNING: CPU: 1 PID: 338 at fs/dcache.c:1597 umount_check+0x179/0x1c0 fs/dcache.c:1588
Modules linked in:
CPU: 1 PID: 338 Comm: syz-executor006 Not tainted 5.4.107-syzkaller-00754-g32de11228337 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:umount_check+0x179/0x1c0 fs/dcache.c:1588
Code: ff 4c 8b 0b 48 81 c5 20 04 00 00 48 c7 c7 e0 e9 e8 84 4c 89 fe 4c 89 f2 4c 89 f9 45 89 e8 31 c0 55 e8 87 db af ff 48 83 c4 08 <0f> 0b e9 fd fe ff ff 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c d4 fe ff
RSP: 0018:ffff8881e97dfa60 EFLAGS: 00010296
RAX: 0000000000000055 RBX: ffffffff85fc1020 RCX: 7c045adca5806000
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffff8881f162d420 R08: ffffffff814e8887 R09: ffffed103ede5e08
R10: ffffed103ede5e08 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000000 R15: ffff8881efb32220
FS:  0000000001b10300(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b01d0 CR3: 0000000005e0e000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 d_walk+0x2d9/0x540 fs/dcache.c:1307
 do_one_tree fs/dcache.c:1604 [inline]
 shrink_dcache_for_umount+0x8a/0x1a0 fs/dcache.c:1620
 generic_shutdown_super+0x63/0x2a0 fs/super.c:447
 kill_anon_super fs/super.c:1108 [inline]
 kill_litter_super+0x71/0xa0 fs/super.c:1117
 deactivate_locked_super+0xaf/0x100 fs/super.c:335
 deactivate_super+0x1b3/0x270 fs/super.c:366
 cleanup_mnt+0x432/0x4e0 fs/namespace.c:1102
 task_work_run+0x186/0x1b0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xcb9/0x2bf0 kernel/exit.c:812
 do_group_exit+0x15c/0x2c0 kernel/exit.c:910
 __do_sys_exit_group+0x13/0x20 kernel/exit.c:921
 __se_sys_exit_group+0x10/0x10 kernel/exit.c:919
 __x64_sys_exit_group+0x37/0x40 kernel/exit.c:919
 do_syscall_64+0xcb/0x1e0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x43e399
Code: Bad RIP value.
RSP: 002b:00007ffd3ba07118 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00000000004af2f0 RCX: 000000000043e399
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001
RBP: 0000000000000001 R08: ffffffffffffffc0 R09: 00000000004aa000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004af2f0
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
---[ end trace d5a6b8c1cf35b53f ]---