BTRFS info (device loop0): enabling ssd optimizations
BTRFS info (device loop0): using spread ssd allocation scheme
BTRFS info (device loop0): turning on sync discard
BTRFS info (device loop0): using free space tree
============================================
WARNING: possible recursive locking detected
6.5.0-rc7-syzkaller-00004-gf7757129e3de-dirty #0 Not tainted
--------------------------------------------
syz-executor.0/5436 is trying to acquire lock:
ffff888021446678 (btrfs-tree-01){.+.+}-{3:3}, at: __btrfs_tree_read_lock+0x2f/0x220 fs/btrfs/locking.c:136

but task is already holding lock:
ffff888021446678 (btrfs-tree-01){.+.+}-{3:3}, at: __btrfs_tree_read_lock+0x2f/0x220 fs/btrfs/locking.c:136

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(btrfs-tree-01);
  lock(btrfs-tree-01);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by syz-executor.0/5436:
 #0: ffff88802accc0e0 (&type->s_umount_key#50/1){+.+.}-{3:3}, at: alloc_super+0x217/0x920 fs/super.c:228
 #1: ffff88802b3ca2d8 (&root->objectid_mutex){+.+.}-{3:3}, at: btrfs_init_fs_root fs/btrfs/disk-io.c:1127 [inline]
 #1: ffff88802b3ca2d8 (&root->objectid_mutex){+.+.}-{3:3}, at: btrfs_get_root_ref+0x5a6/0xae0 fs/btrfs/disk-io.c:1338
 #2: ffff888021446678 (btrfs-tree-01){.+.+}-{3:3}, at: __btrfs_tree_read_lock+0x2f/0x220 fs/btrfs/locking.c:136

stack backtrace:
CPU: 0 PID: 5436 Comm: syz-executor.0 Not tainted 6.5.0-rc7-syzkaller-00004-gf7757129e3de-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 check_deadlock kernel/locking/lockdep.c:3070 [inline]
 validate_chain kernel/locking/lockdep.c:3863 [inline]
 __lock_acquire+0x6a81/0x7f70 kernel/locking/lockdep.c:5144
 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5761
 down_read_nested+0x49/0x2f0 kernel/locking/rwsem.c:1645
 __btrfs_tree_read_lock+0x2f/0x220 fs/btrfs/locking.c:136
 btrfs_tree_read_lock fs/btrfs/locking.c:142 [inline]
 btrfs_read_lock_root_node+0x292/0x3c0 fs/btrfs/locking.c:281
 btrfs_search_slot_get_root fs/btrfs/ctree.c:1832 [inline]
 btrfs_search_slot+0x4ff/0x31d0 fs/btrfs/ctree.c:2155
 btrfs_init_root_free_objectid+0x148/0x320 fs/btrfs/disk-io.c:4955
 btrfs_init_fs_root fs/btrfs/disk-io.c:1128 [inline]
 btrfs_get_root_ref+0x5ae/0xae0 fs/btrfs/disk-io.c:1338
 btrfs_get_fs_root fs/btrfs/disk-io.c:1390 [inline]
 open_ctree+0x29c8/0x3030 fs/btrfs/disk-io.c:3494
 btrfs_fill_super+0x1c7/0x2f0 fs/btrfs/super.c:1154
 btrfs_mount_root+0x7e0/0x910 fs/btrfs/super.c:1519
 legacy_get_tree+0xef/0x190 fs/fs_context.c:611
 vfs_get_tree+0x8c/0x270 fs/super.c:1519
 fc_mount fs/namespace.c:1112 [inline]
 vfs_kern_mount+0xbc/0x150 fs/namespace.c:1142
 btrfs_mount+0x39f/0xb50 fs/btrfs/super.c:1579
 legacy_get_tree+0xef/0x190 fs/fs_context.c:611
 vfs_get_tree+0x8c/0x270 fs/super.c:1519
 do_new_mount+0x28f/0xae0 fs/namespace.c:3335
 do_mount fs/namespace.c:3675 [inline]
 __do_sys_mount fs/namespace.c:3884 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3861
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fb69647e1ea
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 09 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb69720dee8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fb69720df80 RCX: 00007fb69647e1ea
RDX: 00000000200055c0 RSI: 0000000020005600 RDI: 00007fb69720df40
RBP: 00000000200055c0 R08: 00007fb69720df80 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020005600
R13: 00007fb69720df40 R14: 00000000000055a8 R15: 00000000200013c0
 </TASK>