syzbot

loop0: detected capacity change from 0 to 1024
hfsplus: trying to free free bnode 0(1)
============================================
WARNING: possible recursive locking detected
6.1.141-syzkaller #0 Not tainted
--------------------------------------------
syz-executor127/4249 is trying to acquire lock:
ffff8880730f1548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_get_block+0x39b/0x1530 fs/hfsplus/extents.c:260

but task is already holding lock:
ffff8880730f2988 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x28f/0xb30 fs/hfsplus/extents.c:577

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

6 locks held by syz-executor127/4249:
 #0: ffff88801fb46460 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:393
 #1: ffff8880730f1e00 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
 #1: ffff8880730f1e00 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: do_unlinkat+0x178/0x560 fs/namei.c:4373
 #2: ffff8880730f2b80 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #2: ffff8880730f2b80 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: vfs_unlink+0xee/0x600 fs/namei.c:4311
 #3: ffff88801df21998 (&sbi->vh_mutex){+.+.}-{3:3}, at: hfsplus_unlink+0x15a/0x760 fs/hfsplus/dir.c:370
 #4: ffff8880730f2988 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x28f/0xb30 fs/hfsplus/extents.c:577
 #5: ffff88801df218f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_free+0xbf/0x4b0 fs/hfsplus/bitmap.c:182

stack backtrace:
CPU: 1 PID: 4249 Comm: syz-executor127 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 __lock_acquire+0x122f/0x7c50 kernel/locking/lockdep.c:-1
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
 hfsplus_get_block+0x39b/0x1530 fs/hfsplus/extents.c:260
 block_read_full_folio+0x3c9/0xed0 fs/buffer.c:2271
 filemap_read_folio+0x160/0x760 mm/filemap.c:2490
 do_read_cache_folio+0x2a0/0x760 mm/filemap.c:3627
 do_read_cache_page+0x32/0x220 mm/filemap.c:3669
 read_mapping_page include/linux/pagemap.h:791 [inline]
 hfsplus_block_free+0x128/0x4b0 fs/hfsplus/bitmap.c:185
 hfsplus_free_extents+0x176/0xac0 fs/hfsplus/extents.c:363
 hfsplus_file_truncate+0x731/0xb30 fs/hfsplus/extents.c:592
 hfsplus_delete_inode+0x17c/0x230 fs/hfsplus/inode.c:-1
 hfsplus_unlink+0x4c0/0x760 fs/hfsplus/dir.c:405
 vfs_unlink+0x385/0x600 fs/namei.c:4322
 do_unlinkat+0x324/0x560 fs/namei.c:4390
 __do_sys_unlink fs/namei.c:4438 [inline]
 __se_sys_unlink fs/namei.c:4436 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4436
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc9b6b5eaf9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcf8b670f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007fc9b6b5eaf9
RDX: 00007fc9b6b5ddf0 RSI: 0000000000000000 RDI: 0000200000000000
RBP: 00007fc9b6ba705e R08: 0000000000000669 R09: 0000000000000000
R10: 00007ffcf8b66fc0 R11: 0000000000000246 R12: 00007fc9b6ba7066
R13: 00007ffcf8b672d8 R14: 0000000000000001 R15: 00000