loop2: detected capacity change from 0 to 1024
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.2.781/7059 is trying to acquire lock:
ffff88804d7d1548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_get_block+0x3a1/0x15a0 fs/hfsplus/extents.c:260

but task is already holding lock:
ffff88804d7d2988 (&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

4 locks held by syz.2.781/7059:
 #0: ffff88807e72a460 (sb_writers#24){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
 #1: ffff88804d7d2b80 (&sb->s_type->i_mutex_key#33){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff88804d7d2b80 (&sb->s_type->i_mutex_key#33){+.+.}-{3:3}, at: do_truncate+0x198/0x240 fs/open.c:63
 #2: ffff88804d7d2988 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1cd/0x1a50 fs/hfsplus/extents.c:455
 #3: ffff88807af8b8f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x93/0x910 fs/hfsplus/bitmap.c:35

stack backtrace:
CPU: 1 PID: 7059 Comm: syz.2.781 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 __lock_acquire+0x1236/0x7d10 kernel/locking/lockdep.c:-1
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x1e3/0x2400 kernel/locking/mutex.c:596
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 hfsplus_get_block+0x3a1/0x15a0 fs/hfsplus/extents.c:260
 block_read_full_page+0x306/0xd40 fs/buffer.c:2290
 do_read_cache_page+0x8a1/0x1030 mm/filemap.c:-1
 read_mapping_page include/linux/pagemap.h:515 [inline]
 hfsplus_block_allocate+0xf1/0x910 fs/hfsplus/bitmap.c:37
 hfsplus_file_extend+0xb1f/0x1a50 fs/hfsplus/extents.c:466
 hfsplus_get_block+0x430/0x15a0 fs/hfsplus/extents.c:245
 __block_write_begin_int+0x565/0x15d0 fs/buffer.c:2012
 __block_write_begin fs/buffer.c:2062 [inline]
 block_write_begin fs/buffer.c:2122 [inline]
 cont_write_begin+0x598/0x7b0 fs/buffer.c:2471
 hfsplus_write_begin+0x92/0xe0 fs/hfsplus/inode.c:53
 cont_expand_zero fs/buffer.c:2398 [inline]
 cont_write_begin+0x263/0x7b0 fs/buffer.c:2461
 hfsplus_write_begin+0x92/0xe0 fs/hfsplus/inode.c:53
 generic_cont_expand_simple+0xf0/0x1a0 fs/buffer.c:2362
 hfsplus_setattr+0x165/0x280 fs/hfsplus/inode.c:281
 notify_change+0xbcd/0xee0 fs/attr.c:505
 do_truncate+0x1ac/0x240 fs/open.c:65
 vfs_truncate+0x262/0x2f0 fs/open.c:111
 do_sys_truncate+0xf2/0x1c0 fs/open.c:134
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fbcf428ccb9
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:00007fbcf24e8028 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007fbcf4507fa0 RCX: 00007fbcf428ccb9
RDX: 0000000000000000 RSI: 000000000000e4a0 RDI: 0000200000001c40
RBP: 00007fbcf42fabf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbcf4508038 R14: 00007fbcf4507fa0 R15: 00007ffff70f9058
 </TASK>