loop0: detected capacity change from 0 to 1024
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.17/4423 is trying to acquire lock:
ffff888079dd1548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_get_block+0x3a1/0x15a0 fs/hfsplus/extents.c:260

but task is already holding lock:
ffff888079dd07c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1cd/0x1a50 fs/hfsplus/extents.c:455

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

       CPU0
       ----
  lock(&HFSPLUS_I(inode)->extents_lock);
  lock(&HFSPLUS_I(inode)->extents_lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz.0.17/4423:
 #0: ffff888072e0c0e0 (&type->s_umount_key#52/1){+.+.}-{3:3}, at: alloc_super+0x1fa/0x930 fs/super.c:228
 #1: ffff88807ab34998 (&sbi->vh_mutex){+.+.}-{3:3}, at: hfsplus_fill_super+0x143a/0x1e70 fs/hfsplus/super.c:572
 #2: ffff88807318a0b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
 #3: ffff888079dd07c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1cd/0x1a50 fs/hfsplus/extents.c:455
 #4: ffff88807ab348f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x92/0x8a0 fs/hfsplus/bitmap.c:35

stack backtrace:
CPU: 0 PID: 4423 Comm: syz.0.17 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
 hfsplus_get_block+0x3a1/0x15a0 fs/hfsplus/extents.c:260
 block_read_full_folio+0x3e6/0xf00 fs/buffer.c:2271
 filemap_read_folio+0x16b/0x770 mm/filemap.c:2490
 do_read_cache_folio+0x2a0/0x760 mm/filemap.c:3659
 do_read_cache_page+0x32/0x220 mm/filemap.c:3701
 read_mapping_page include/linux/pagemap.h:793 [inline]
 hfsplus_block_allocate+0xdc/0x8a0 fs/hfsplus/bitmap.c:37
 hfsplus_file_extend+0xb1f/0x1a50 fs/hfsplus/extents.c:466
 hfsplus_bmap_reserve+0x11e/0x4f0 fs/hfsplus/btree.c:358
 hfsplus_create_cat+0x1c7/0x10c0 fs/hfsplus/catalog.c:272
 hfsplus_fill_super+0x14b8/0x1e70 fs/hfsplus/super.c:579
 mount_bdev+0x287/0x3c0 fs/super.c:1443
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:632
 vfs_get_tree+0x88/0x270 fs/super.c:1573
 do_new_mount+0x24a/0xa40 fs/namespace.c:3078
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606
 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: 0033:0x7f960a79da0a
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe9dcfef18 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffe9dcfefa0 RCX: 00007f960a79da0a
RDX: 00002000000000c0 RSI: 0000200000000080 RDI: 00007ffe9dcfef60
RBP: 00002000000000c0 R08: 00007ffe9dcfefa0 R09: 0000000000810808
R10: 0000000000810808 R11: 0000000000000246 R12: 0000200000000080
R13: 00007ffe9dcfef60 R14: 00000000000006a3 R15: 00002000000008c0
 </TASK>
hfsplus: b-tree write err: -5, ino 25