------------[ cut here ]------------
WARNING: CPU: 0 PID: 29126 at fs/btrfs/volumes.c:1168 close_fs_devices+0x763/0x880 fs/btrfs/volumes.c:1168
Modules linked in:
CPU: 1 PID: 29126 Comm: syz-executor.2 Not tainted 5.13.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:close_fs_devices+0x763/0x880 fs/btrfs/volumes.c:1168
Code: c4 38 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 65 98 18 fe 0f 0b e9 29 f9 ff ff e8 59 98 18 fe 0f 0b e9 3c ff ff ff e8 4d 98 18 fe <0f> 0b e9 69 ff ff ff 48 c7 c1 94 65 38 8e 80 e1 07 80 c1 03 38 c1
RSP: 0018:ffffc9001875f310 EFLAGS: 00010283
RAX: ffffffff836672c3 RBX: 0000000000000001 RCX: 0000000000040000
RDX: ffffc9000d8a0000 RSI: 000000000001a3ca RDI: 000000000001a3cb
RBP: ffff88801ded9d08 R08: ffffffff83667225 R09: ffffed1003f7bb28
R10: ffffed1003f7bb28 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff88801fbdd868 R14: 1ffff11003f7bb0d R15: 1ffff11003f7bb0a
FS:  00007f69c2fe4700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3004e83000 CR3: 000000002e190000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 btrfs_close_devices+0xc9/0x450 fs/btrfs/volumes.c:1180
 open_ctree+0x8d4/0x37b8 fs/btrfs/disk-io.c:3703
 btrfs_fill_super fs/btrfs/super.c:1382 [inline]
 btrfs_mount_root+0xac5/0xc60 fs/btrfs/super.c:1749
 legacy_get_tree+0xea/0x180 fs/fs_context.c:592
 vfs_get_tree+0x86/0x270 fs/super.c:1498
 fc_mount fs/namespace.c:993 [inline]
 vfs_kern_mount+0xc9/0x160 fs/namespace.c:1023
 btrfs_mount+0x3d3/0xb50 fs/btrfs/super.c:1809
 legacy_get_tree+0xea/0x180 fs/fs_context.c:592
 vfs_get_tree+0x86/0x270 fs/super.c:1498
 do_new_mount fs/namespace.c:2905 [inline]
 path_mount+0x196f/0x2be0 fs/namespace.c:3235
 do_mount fs/namespace.c:3248 [inline]
 __do_sys_mount fs/namespace.c:3456 [inline]
 __se_sys_mount+0x2f9/0x3b0 fs/namespace.c:3433
 do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x467afa
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:00007f69c2fe3fa8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 0000000000467afa
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f69c2fe4000
RBP: 00007f69c2fe4040 R08: 00007f69c2fe4040 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000
R13: 0000000020000100 R14: 00007f69c2fe4000 R15: 0000000020016a00