============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.4.15/4442 is trying to acquire lock:
ffff888079d3e0b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x15b/0x1d0 fs/hfs/bfind.c:-1

but task is already holding lock:
ffff888079d3e0b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x15b/0x1d0 fs/hfs/bfind.c:-1

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

       CPU0
       ----
  lock(&tree->tree_lock/1);
  lock(&tree->tree_lock/1);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz.4.15/4442:
 #0: ffff88807af72460 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402
 #1: ffff8880532b1628 (&sb->s_type->i_mutex_key#23){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff8880532b1628 (&sb->s_type->i_mutex_key#23){+.+.}-{3:3}, at: do_truncate+0x198/0x240 fs/open.c:63
 #2: ffff8880532b1478 (&HFS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xfb/0x13f0 fs/hfs/extent.c:397
 #3: ffff888079d3e0b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x15b/0x1d0 fs/hfs/bfind.c:-1
 #4: ffff8880532b00f8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xfb/0x13f0 fs/hfs/extent.c:397

stack backtrace:
CPU: 1 PID: 4442 Comm: syz.4.15 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 __lock_acquire+0x123e/0x7d10 kernel/locking/lockdep.c:-1
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x12d/0xaf0 kernel/locking/mutex.c:747
 hfs_find_init+0x15b/0x1d0 fs/hfs/bfind.c:-1
 hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
 hfs_extend_file+0x35d/0x13f0 fs/hfs/extent.c:401
 hfs_bmap_reserve+0x103/0x420 fs/hfs/btree.c:234
 __hfs_ext_write_extent+0x1fa/0x470 fs/hfs/extent.c:121
 __hfs_ext_cache_extent+0x6b/0x9b0 fs/hfs/extent.c:174
 hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
 hfs_extend_file+0x39c/0x13f0 fs/hfs/extent.c:401
 hfs_get_block+0x40f/0xc50 fs/hfs/extent.c:353
 __block_write_begin_int+0x55d/0x1a80 fs/buffer.c:1991
 __block_write_begin fs/buffer.c:2041 [inline]
 block_write_begin+0x96/0x1e0 fs/buffer.c:2102
 cont_write_begin+0x5ea/0x800 fs/buffer.c:2456
 hfs_write_begin+0x87/0xd0 fs/hfs/inode.c:58
 cont_expand_zero fs/buffer.c:2383 [inline]
 cont_write_begin+0x2ad/0x800 fs/buffer.c:2446
 hfs_write_begin+0x87/0xd0 fs/hfs/inode.c:58
 hfs_file_truncate+0x1c0/0xa10 fs/hfs/extent.c:494
 hfs_inode_setattr+0x4ab/0x6f0 fs/hfs/inode.c:659
 notify_change+0xc74/0xf40 fs/attr.c:499
 do_truncate+0x1ac/0x240 fs/open.c:65
 vfs_truncate+0x262/0x2f0 fs/open.c:111
 do_sys_truncate+0xf2/0x1c0 fs/open.c:134
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fca5cd9bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fca5dbb4028 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007fca5d015fa0 RCX: 00007fca5cd9bf79
RDX: 0000000000000000 RSI: 0000000003000000 RDI: 0000200000000900
RBP: 00007fca5ce327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fca5d016038 R14: 00007fca5d015fa0 R15: 00007ffd7dee09f8
 </TASK>