BUG: Dentry ffff8881199a8550{i=0,n=.index}  still in use (1) [unmount of 9p 9p]
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WARNING: CPU: 1 PID: 366 at fs/dcache.c:1616 umount_check+0x18d/0x1d0 fs/dcache.c:1607
Modules linked in:
CPU: 1 PID: 366 Comm: syz-executor584 Not tainted 5.10.75-syzkaller-01082-g234d53d2bb60 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:umount_check+0x18d/0x1d0 fs/dcache.c:1607
Code: 8b 0b 49 81 c6 f8 03 00 00 48 c7 c7 40 43 2e 85 4c 89 e6 48 8b 55 d0 4c 89 e1 45 89 f8 31 c0 41 56 e8 ae d9 9e ff 48 83 c4 08 <0f> 0b e9 f1 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c c9 fe ff
RSP: 0018:ffffc90000b87a98 EFLAGS: 00010282
RAX: 000000000000004f RBX: ffffffff866d8540 RCX: 8700b28fb0854d00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffffc90000b87ac8 R08: ffffffff81545368 R09: 0000000000000003
R10: fffff52000170ea5 R11: 0000000000000004 R12: ffff8881199a8550
R13: dffffc0000000000 R14: ffff88811d73d3f8 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005579c33941f0 CR3: 000000010c13f000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 d_walk+0x309/0x540 fs/dcache.c:1326
 do_one_tree fs/dcache.c:1623 [inline]
 shrink_dcache_for_umount+0x8e/0x1b0 fs/dcache.c:1639
 generic_shutdown_super+0x66/0x2c0 fs/super.c:447
 kill_anon_super+0x3c/0x70 fs/super.c:1108
 v9fs_kill_super+0x4c/0x90 fs/9p/vfs_super.c:221
 deactivate_locked_super+0xb0/0x100 fs/super.c:335
 deactivate_super+0xa5/0xd0 fs/super.c:366
 cleanup_mnt+0x45f/0x510 fs/namespace.c:1118
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1125
 task_work_run+0x147/0x1b0 kernel/task_work.c:154
 exit_task_work include/linux/task_work.h:30 [inline]
 do_exit+0x70e/0x23a0 kernel/exit.c:813
 do_group_exit+0x16a/0x2d0 kernel/exit.c:910
 __do_sys_exit_group+0x17/0x20 kernel/exit.c:921
 __se_sys_exit_group+0x14/0x20 kernel/exit.c:919
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:919
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fe9c3d0c9a9
Code: Unable to access opcode bytes at RIP 0x7fe9c3d0c97f.
RSP: 002b:00007ffc8fc03a28 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fe9c3d813f0 RCX: 00007fe9c3d0c9a9
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001
RBP: 0000000000000001 R08: ffffffffffffffc0 R09: 00007fe9c3d7be40
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe9c3d813f0
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
---[ end trace e6d20d49fe0907e1 ]---
VFS: Busy inodes after unmount of 9p. Self-destruct in 5 seconds.  Have a nice day...
9pnet: Found fid 0 not clunked
9pnet: Found fid 1 not clunked