------------[ cut here ]------------
WARNING: CPU: 0 PID: 8403 at fs/btrfs/volumes.c:1168 close_fs_devices+0x772/0x9a0 fs/btrfs/volumes.c:1168
Modules linked in:
CPU: 1 PID: 8403 Comm: syz-executor.3 Not tainted 5.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:close_fs_devices+0x772/0x9a0 fs/btrfs/volumes.c:1168
Code: e8 83 e7 37 fe 85 db 0f 85 07 f9 ff ff e8 c6 df 37 fe 0f 0b e9 fb f8 ff ff e8 ba df 37 fe 0f 0b e9 e2 fd ff ff e8 ae df 37 fe <0f> 0b e9 19 fe ff ff 48 c7 c7 0c 5b c5 8d e8 db 92 7b fe e9 bb f8
RSP: 0018:ffffc90001b1fbe8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff888014c53880 RSI: ffffffff833c11d2 RDI: 0000000000000003
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffff888018ef393b
R10: ffffffff833c0fe9 R11: 0000000000000000 R12: ffff888018ef3938
R13: 0000000000000000 R14: ffff888012f45508 R15: ffff888018ef3850
FS:  0000000001919400(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000025d9708 CR3: 0000000076e5d000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 btrfs_close_devices+0x8e/0x4b0 fs/btrfs/volumes.c:1180
 close_ctree+0x746/0x789 fs/btrfs/disk-io.c:4343
 generic_shutdown_super+0x144/0x370 fs/super.c:464
 kill_anon_super+0x36/0x60 fs/super.c:1056
 btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2353
 deactivate_locked_super+0x94/0x160 fs/super.c:335
 deactivate_super+0xad/0xd0 fs/super.c:366
 cleanup_mnt+0x3a3/0x530 fs/namespace.c:1136
 task_work_run+0xdd/0x1a0 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4678b7
Code: ff d0 48 89 c7 b8 3c 00 00 00 0f 05 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffecef05728 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000004678b7
RDX: 00007ffecef057fc RSI: 0000000000000002 RDI: 00007ffecef057f0
RBP: 00007ffecef057f0 R08: 00000000ffffffff R09: 00007ffecef055c0
R10: 000000000191a8e3 R11: 0000000000000246 R12: 00000000004bebb2
R13: 00007ffecef068c0 R14: 000000000191a810 R15: 00007ffecef06900