VFS: Busy inodes after unmount of loop4 (btrfs)
------------[ cut here ]------------
kernel BUG at fs/super.c:496!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 3672 Comm: syz-executor.4 Not tainted 6.1.20-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
RIP: 0010:generic_shutdown_super+0x339/0x340 fs/super.c:494
Code: 8b 1b 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 19 f8 f0 ff 48 8b 13 48 c7 c7 a0 12 f9 8a 4c 89 fe e8 a0 74 98 08 <0f> 0b 0f 1f 44 00 00 41 57 41 56 53 49 89 fe 49 bf 00 00 00 00 00
RSP: 0018:ffffc900042cfcf0 EFLAGS: 00010246
RAX: 000000000000002f RBX: ffffffff8d437e60 RCX: 860cba9235d7de00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff11007979cfb R08: ffffffff816e120c R09: fffff52000859f55
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8b2d0818 R15: ffff88803cbce6a8
FS:  0000555555a1b400(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001842 CR3: 000000003649a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kill_anon_super+0x37/0x60 fs/super.c:1099
 btrfs_kill_super+0x3d/0x50 fs/btrfs/super.c:2441
 deactivate_locked_super+0xa0/0x110 fs/super.c:332
 cleanup_mnt+0x490/0x520 fs/namespace.c:1186
 task_work_run+0x246/0x300 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xd9/0x100 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x60/0x2d0 kernel/entry/common.c:296
 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6da468d567
Code: ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdfaf41f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f6da468d567
RDX: 00007ffdfaf4202a RSI: 000000000000000a RDI: 00007ffdfaf42020
RBP: 00007ffdfaf42020 R08: 00000000ffffffff R09: 00007ffdfaf41df0
R10: 0000555555a1c903 R11: 0000000000000246 R12: 00007f6da46e6b74
R13: 00007ffdfaf430e0 R14: 0000555555a1c810 R15: 00007ffdfaf43120
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:generic_shutdown_super+0x339/0x340 fs/super.c:494
Code: 8b 1b 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 19 f8 f0 ff 48 8b 13 48 c7 c7 a0 12 f9 8a 4c 89 fe e8 a0 74 98 08 <0f> 0b 0f 1f 44 00 00 41 57 41 56 53 49 89 fe 49 bf 00 00 00 00 00
RSP: 0018:ffffc900042cfcf0 EFLAGS: 00010246
RAX: 000000000000002f RBX: ffffffff8d437e60 RCX: 860cba9235d7de00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff11007979cfb R08: ffffffff816e120c R09: fffff52000859f55
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8b2d0818 R15: ffff88803cbce6a8
FS:  0000555555a1b400(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbce8b821b8 CR3: 000000003649a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400