loop4: detected capacity change from 0 to 64
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.4.256/7342 is trying to acquire lock:
ffff8880323300f8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xda/0x1540 fs/hfs/extent.c:397

but task is already holding lock:
ffff888032330778 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xda/0x1540 fs/hfs/extent.c:397

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

       CPU0
       ----
  lock(&HFS_I(tree->inode)->extents_lock);
  lock(&HFS_I(tree->inode)->extents_lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz.4.256/7342:
 #0: ffff88806354e420 (sb_writers#31){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499
 #1: ffff888032330fa0 (&type->i_mutex_dir_key#21){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #1: ffff888032330fa0 (&type->i_mutex_dir_key#21){+.+.}-{4:4}, at: open_last_lookups fs/namei.c:4536 [inline]
 #1: ffff888032330fa0 (&type->i_mutex_dir_key#21){+.+.}-{4:4}, at: path_openat+0xb4c/0x3840 fs/namei.c:4783
 #2: ffff8880778e60b0 (&tree->tree_lock#2){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300 fs/hfs/bfind.c:-1
 #3: ffff888032330778 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xda/0x1540 fs/hfs/extent.c:397
 #4: ffff8880778e40b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300 fs/hfs/bfind.c:-1

stack backtrace:
CPU: 0 UID: 0 PID: 7342 Comm: syz.4.256 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_deadlock_bug+0x279/0x290 kernel/locking/lockdep.c:3041
 check_deadlock kernel/locking/lockdep.c:3093 [inline]
 validate_chain kernel/locking/lockdep.c:3895 [inline]
 __lock_acquire+0x2540/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
 __mutex_lock_common kernel/locking/mutex.c:614 [inline]
 __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776
 hfs_extend_file+0xda/0x1540 fs/hfs/extent.c:397
 hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269
 __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+0x31e/0x1540 fs/hfs/extent.c:401
 hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269
 hfs_cat_create+0x1c5/0x770 fs/hfs/catalog.c:104
 hfs_create+0x66/0xe0 fs/hfs/dir.c:202
 lookup_open fs/namei.c:4439 [inline]
 open_last_lookups fs/namei.c:4539 [inline]
 path_openat+0x1387/0x3840 fs/namei.c:4783
 do_filp_open+0x1fa/0x410 fs/namei.c:4813
 do_sys_openat2+0x121/0x200 fs/open.c:1391
 do_sys_open fs/open.c:1397 [inline]
 __do_sys_open fs/open.c:1405 [inline]
 __se_sys_open fs/open.c:1401 [inline]
 __x64_sys_open+0x11e/0x150 fs/open.c:1401
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f192658f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f19274b5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f19267e5fa0 RCX: 00007f192658f749
RDX: 0000000000000000 RSI: 000000000002a4c0 RDI: 0000200000000140
RBP: 00007f1926613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f19267e6038 R14: 00007f19267e5fa0 R15: 00007ffcb57e4078
 </TASK>
hfs: new node 0 already hashed?
------------[ cut here ]------------
WARNING: fs/hfs/bnode.c:520 at hfs_bnode_create+0x461/0x4f0 fs/hfs/bnode.c:520, CPU#1: syz.4.256/7342
Modules linked in:

CPU: 1 UID: 0 PID: 7342 Comm: syz.4.256 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:hfs_bnode_create+0x461/0x4f0 fs/hfs/bnode.c:520
Code: a2 8b 89 ee e8 40 34 85 fe e9 cf fc ff ff e8 a6 42 1f ff 4c 89 ef e8 de d8 bd 08 48 c7 c7 c0 ba a2 8b 89 ee e8 20 34 85 fe 90 <0f> 0b 90 eb b0 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c d6 fb ff ff
RSP: 0018:ffffc900031f7040 EFLAGS: 00010246
RAX: 000000000000001f RBX: ffff8880778e4000 RCX: 5b6f188d97d0f300
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffc900031f6d67 R09: 1ffff9200063edac
R10: dffffc0000000000 R11: fffff5200063edad R12: 0000000000000000
R13: ffff8880778e40e0 R14: ffff888075437100 R15: dffffc0000000000
FS:  00007f19274b56c0(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055cff8d1c008 CR3: 0000000078e52000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 hfs_bmap_alloc+0x5bb/0x640 fs/hfs/btree.c:326
 hfs_btree_inc_height+0xf6/0xac0 fs/hfs/brec.c:490
 hfs_brec_insert+0x7ee/0xc80 fs/hfs/brec.c:148
 __hfs_ext_write_extent+0x2a1/0x470 fs/hfs/extent.c:124
 __hfs_ext_cache_extent+0x6b/0x9b0 fs/hfs/extent.c:174
 hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
 hfs_extend_file+0x31e/0x1540 fs/hfs/extent.c:401
 hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269
 hfs_cat_create+0x1c5/0x770 fs/hfs/catalog.c:104
 hfs_create+0x66/0xe0 fs/hfs/dir.c:202
 lookup_open fs/namei.c:4439 [inline]
 open_last_lookups fs/namei.c:4539 [inline]
 path_openat+0x1387/0x3840 fs/namei.c:4783
 do_filp_open+0x1fa/0x410 fs/namei.c:4813
 do_sys_openat2+0x121/0x200 fs/open.c:1391
 do_sys_open fs/open.c:1397 [inline]
 __do_sys_open fs/open.c:1405 [inline]
 __se_sys_open fs/open.c:1401 [inline]
 __x64_sys_open+0x11e/0x150 fs/open.c:1401
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f192658f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f19274b5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f19267e5fa0 RCX: 00007f192658f749
RDX: 0000000000000000 RSI: 000000000002a4c0 RDI: 0000200000000140
RBP: 00007f1926613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f19267e6038 R14: 00007f19267e5fa0 R15: 00007ffcb57e4078
 </TASK>