------------[ cut here ]------------
WARNING: CPU: 1 PID: 30973 at fs/btrfs/volumes.c:1168 close_fs_devices+0x772/0x9a0 fs/btrfs/volumes.c:1168
Modules linked in:
CPU: 0 PID: 30973 Comm: syz-executor.0 Not tainted 5.12.0-rc8-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 33 62 38 fe 85 db 0f 85 07 f9 ff ff e8 d6 5b 38 fe 0f 0b e9 fb f8 ff ff e8 ca 5b 38 fe 0f 0b e9 e2 fd ff ff e8 be 5b 38 fe <0f> 0b e9 19 fe ff ff 48 c7 c7 cc 26 c5 8d e8 eb 91 7b fe e9 bb f8
RSP: 0000:ffffc9001845f748 EFLAGS: 00010246
RAX: 0000000000040000 RBX: 0000000000000001 RCX: ffffc90001fe9000
RDX: 0000000000040000 RSI: ffffffff833acde2 RDI: 0000000000000003
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffff88801df4293b
R10: ffffffff833acbf9 R11: 0000000000000000 R12: ffff88801df42938
R13: 0000000000000000 R14: ffff888017b11908 R15: ffff88801df42850
FS:  00007f3a36e7f700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3d633f7000 CR3: 0000000012f47000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 btrfs_close_devices+0x8e/0x4b0 fs/btrfs/volumes.c:1180
 open_ctree+0x407a/0x411f fs/btrfs/disk-io.c:3599
 btrfs_fill_super fs/btrfs/super.c:1356 [inline]
 btrfs_mount_root.cold+0x14/0x165 fs/btrfs/super.c:1723
 legacy_get_tree+0x105/0x220 fs/fs_context.c:592
 vfs_get_tree+0x89/0x2f0 fs/super.c:1497
 fc_mount fs/namespace.c:993 [inline]
 vfs_kern_mount.part.0+0xd3/0x170 fs/namespace.c:1023
 vfs_kern_mount+0x3c/0x60 fs/namespace.c:1010
 btrfs_mount+0x234/0xa20 fs/btrfs/super.c:1783
 legacy_get_tree+0x105/0x220 fs/fs_context.c:592
 vfs_get_tree+0x89/0x2f0 fs/super.c:1497
 do_new_mount fs/namespace.c:2903 [inline]
 path_mount+0x132a/0x1f90 fs/namespace.c:3233
 do_mount fs/namespace.c:3246 [inline]
 __do_sys_mount fs/namespace.c:3454 [inline]
 __se_sys_mount fs/namespace.c:3431 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3431
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x467b1a
Code: 48 c7 c2 bc ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 b8 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 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:00007f3a36e7efa8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 0000000000467b1a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f3a36e7f000
RBP: 00007f3a36e7f040 R08: 00007f3a36e7f040 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000020000000
R13: 0000000020000100 R14: 00007f3a36e7f000 R15: 0000000020016800