VFS: Busy inodes after unmount of loop4 (btrfs)
------------[ cut here ]------------
kernel BUG at fs/super.c:649!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 0 PID: 5737 Comm: syz-executor.4 Not tainted 6.9.0-rc6-syzkaller-00046-g18daea77cca6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:generic_shutdown_super+0x31b/0x3d0 fs/super.c:649
Code: 28 48 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 aa 00 00 00 48 8b 55 00 48 8d b3 68 06 00 00 48 c7 c7 a0 fa 1c 8b e8 06 b9 74 ff 90 <0f> 0b e8 ee 5a ef ff e9 2f fd ff ff e8 e4 5a ef ff e9 02 fd ff ff
RSP: 0018:ffffc900045cfd78 EFLAGS: 00010282
RAX: 000000000000002f RBX: ffff88807b016000 RCX: ffffffff816e7b29
RDX: 0000000000000000 RSI: ffffffff816f0866 RDI: 0000000000000005
RBP: ffffffff8df02340 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000001 R12: ffff88807b0169c0
R13: ffff88807b016788 R14: 0000000000000000 R15: ffff88807e09ac80
FS:  000055556be05480(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f47e97c0000 CR3: 0000000069e68000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kill_anon_super+0x3a/0x60 fs/super.c:1225
 btrfs_kill_super+0x3b/0x50 fs/btrfs/super.c:2091
 deactivate_locked_super+0xbe/0x1a0 fs/super.c:472
 deactivate_super+0xde/0x100 fs/super.c:505
 cleanup_mnt+0x222/0x450 fs/namespace.c:1267
 task_work_run+0x14e/0x250 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xdc/0x260 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa02247f1d7
Code: b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 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 00 f0 ff ff 77 01 c3 48 c7 c2 b0 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007fff4472e8a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fa02247f1d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff4472e960
RBP: 00007fff4472e960 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fff4472fa20
R13: 00007fa0224c93b9 R14: 000000000002b23d R15: 0000000000000007
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:generic_shutdown_super+0x31b/0x3d0 fs/super.c:649
Code: 28 48 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 aa 00 00 00 48 8b 55 00 48 8d b3 68 06 00 00 48 c7 c7 a0 fa 1c 8b e8 06 b9 74 ff 90 <0f> 0b e8 ee 5a ef ff e9 2f fd ff ff e8 e4 5a ef ff e9 02 fd ff ff
RSP: 0018:ffffc900045cfd78 EFLAGS: 00010282
RAX: 000000000000002f RBX: ffff88807b016000 RCX: ffffffff816e7b29
RDX: 0000000000000000 RSI: ffffffff816f0866 RDI: 0000000000000005
RBP: ffffffff8df02340 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000001 R12: ffff88807b0169c0
R13: ffff88807b016788 R14: 0000000000000000 R15: ffff88807e09ac80
FS:  000055556be05480(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558fb8e978 CR3: 0000000069e68000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400