loop0: detected capacity change from 0 to 1024
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.17/6028 is trying to acquire lock:
ffff888032770108 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x1f8/0x1c30 fs/hfsplus/extents.c:453

but task is already holding lock:
ffff8880327722c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_ext_write_extent+0x8a/0x200 fs/hfsplus/extents.c:149

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

4 locks held by syz.0.17/6028:
 #0: ffff88807b9d8420 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2680 [inline]
 #0: ffff88807b9d8420 (sb_writers#12){.+.+}-{0:0}, at: vfs_write+0x211/0xb30 fs/read_write.c:682
 #1: ffff8880327724b8 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #1: ffff8880327724b8 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: hfsplus_file_fsync+0x124/0x590 fs/hfsplus/inode.c:334
 #2: ffff8880327722c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_ext_write_extent+0x8a/0x200 fs/hfsplus/extents.c:149
 #3: ffff88807b9da0b0 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfsplus_find_init+0x168/0x2d0 fs/hfsplus/bfind.c:28

stack backtrace:
CPU: 1 UID: 0 PID: 6028 Comm: syz.0.17 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
 hfsplus_file_extend+0x1f8/0x1c30 fs/hfsplus/extents.c:453
 hfsplus_bmap_reserve+0x125/0x510 fs/hfsplus/btree.c:358
 __hfsplus_ext_write_extent+0x28d/0x5b0 fs/hfsplus/extents.c:104
 hfsplus_ext_write_extent_locked fs/hfsplus/extents.c:139 [inline]
 hfsplus_ext_write_extent+0x17a/0x200 fs/hfsplus/extents.c:150
 hfsplus_write_inode+0x2c/0x660 fs/hfsplus/super.c:168
 write_inode fs/fs-writeback.c:1582 [inline]
 __writeback_single_inode+0x7e1/0x1240 fs/fs-writeback.c:1802
 writeback_single_inode+0x493/0xc70 fs/fs-writeback.c:1858
 sync_inode_metadata+0xb9/0x110 fs/fs-writeback.c:2944
 hfsplus_file_fsync+0x131/0x590 fs/hfsplus/inode.c:339
 generic_write_sync include/linux/fs.h:2615 [inline]
 generic_file_write_iter+0x319/0x550 mm/filemap.c:4461
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:686
 ksys_pwrite64 fs/read_write.c:793 [inline]
 __do_sys_pwrite64 fs/read_write.c:801 [inline]
 __se_sys_pwrite64 fs/read_write.c:798 [inline]
 __x64_sys_pwrite64+0x193/0x220 fs/read_write.c:798
 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: 0033:0x7f26ed18f749
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:00007ffe672c7f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f26ed3e5fa0 RCX: 00007f26ed18f749
RDX: 0000000000000001 RSI: 0000200000000140 RDI: 0000000000000004
RBP: 00007f26ed213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000feca R11: 0000000000000246 R12: 0000000000000000
R13: 00007f26ed3e5fa0 R14: 00007f26ed3e5fa0 R15: 0000000000000004
 </TASK>