loop0: detected capacity change from 0 to 64
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.17/4470 is trying to acquire lock:
ffff888020b3e0b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x14e/0x1d0 fs/hfs/bfind.c:-1

but task is already holding lock:
ffff888020b3e0b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x14e/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.0.17/4470:
 #0: ffff888023d0e460 (sb_writers#13){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
 #1: ffff888077b59518 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline]
 #1: ffff888077b59518 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: generic_file_write_iter+0x7f/0x2e0 mm/filemap.c:3986
 #2: ffff888077b59368 (&HFS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xe7/0x1380 fs/hfs/extent.c:397
 #3: ffff888020b3e0b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x14e/0x1d0 fs/hfs/bfind.c:-1
 #4: ffff888077b580a8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xe7/0x1380 fs/hfs/extent.c:397

stack backtrace:
CPU: 1 PID: 4470 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 check_deadlock kernel/locking/lockdep.c:3090 [inline]
 validate_chain kernel/locking/lockdep.c:3884 [inline]
 __lock_acquire+0x690e/0x7ea0 kernel/locking/lockdep.c:5171
 lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x12d/0xb40 kernel/locking/mutex.c:747
 hfs_find_init+0x14e/0x1d0 fs/hfs/bfind.c:-1
 hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
 hfs_extend_file+0x339/0x1380 fs/hfs/extent.c:401
 hfs_bmap_reserve+0x104/0x420 fs/hfs/btree.c:234
 __hfs_ext_write_extent+0x1fc/0x470 fs/hfs/extent.c:121
 __hfs_ext_cache_extent+0x6e/0x9a0 fs/hfs/extent.c:174
 hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
 hfs_extend_file+0x378/0x1380 fs/hfs/extent.c:401
 hfs_get_block+0x3fe/0xbe0 fs/hfs/extent.c:353
 __block_write_begin_int+0x577/0x1ab0 fs/buffer.c:1991
 __block_write_begin fs/buffer.c:2041 [inline]
 block_write_begin+0x96/0x1e0 fs/buffer.c:2102
 cont_write_begin+0x5f9/0x800 fs/buffer.c:2456
 hfs_write_begin+0x87/0xd0 fs/hfs/inode.c:59
 generic_perform_write+0x2fa/0x5c0 mm/filemap.c:3862
 __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960
 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:3989
 call_write_iter include/linux/fs.h:2271 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x482/0x9a0 fs/read_write.c:584
 ksys_write+0x14d/0x260 fs/read_write.c:637
 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: 0033:0x7fd98f19f559
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:00007fff257eefc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd98f425fa0 RCX: 00007fd98f19f559
RDX: 00000000000ffe00 RSI: 0000200000004200 RDI: 0000000000000004
RBP: 00007fd98f236b50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd98f425fac R14: 00007fd98f425fa0 R15: 00007fd98f425fa0
 </TASK>