loop1: detected capacity change from 0 to 1024
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.1.318/6504 is trying to acquire lock:
ffff0001087b1548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_get_block+0x2c0/0x11a0 fs/hfsplus/extents.c:260

but task is already holding lock:
ffff0001087b2988 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x18c/0x13b4 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

3 locks held by syz.1.318/6504:
 #0: ffff0001087b2b80 (&sb->s_type->i_mutex_key#43){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #0: ffff0001087b2b80 (&sb->s_type->i_mutex_key#43){+.+.}-{3:3}, at: generic_file_write_iter+0x84/0x2b0 mm/filemap.c:3986
 #1: ffff0001087b2988 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x18c/0x13b4 fs/hfsplus/extents.c:455
 #2: ffff0000dcd430f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x88/0x7e4 fs/hfsplus/bitmap.c:35

stack backtrace:
CPU: 0 PID: 6504 Comm: syz.1.318 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
Call trace:
 dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 __lock_acquire+0x15cc/0x6800 kernel/locking/lockdep.c:-1
 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662
 __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 hfsplus_get_block+0x2c0/0x11a0 fs/hfsplus/extents.c:260
 block_read_full_folio+0x2f4/0x980 fs/buffer.c:2271
 hfsplus_read_folio+0x28/0x38 fs/hfsplus/inode.c:28
 filemap_read_folio+0x134/0x384 mm/filemap.c:2490
 do_read_cache_folio+0x24c/0x538 mm/filemap.c:3659
 do_read_cache_page mm/filemap.c:3701 [inline]
 read_cache_page+0x6c/0x184 mm/filemap.c:3710
 read_mapping_page include/linux/pagemap.h:793 [inline]
 hfsplus_block_allocate+0xd8/0x7e4 fs/hfsplus/bitmap.c:37
 hfsplus_file_extend+0x7a0/0x13b4 fs/hfsplus/extents.c:466
 hfsplus_get_block+0x324/0x11a0 fs/hfsplus/extents.c:245
 __block_write_begin_int+0x350/0x1388 fs/buffer.c:1991
 __block_write_begin fs/buffer.c:2041 [inline]
 block_write_begin fs/buffer.c:2102 [inline]
 cont_write_begin+0x53c/0x780 fs/buffer.c:2456
 hfsplus_write_begin+0x98/0xe4 fs/hfsplus/inode.c:52
 cont_expand_zero fs/buffer.c:2416 [inline]
 cont_write_begin+0x5d8/0x780 fs/buffer.c:2446
 hfsplus_write_begin+0x98/0xe4 fs/hfsplus/inode.c:52
 generic_perform_write+0x234/0x4f4 mm/filemap.c:3862
 __generic_file_write_iter+0x130/0x250 mm/filemap.c:3960
 generic_file_write_iter+0xb4/0x2b0 mm/filemap.c:3989
 call_write_iter include/linux/fs.h:2265 [inline]
 aio_write+0x570/0x7dc fs/aio.c:1615
 __io_submit_one fs/aio.c:-1 [inline]
 io_submit_one+0x7c4/0x11d8 fs/aio.c:2034
 __do_sys_io_submit fs/aio.c:2093 [inline]
 __se_sys_io_submit fs/aio.c:2063 [inline]
 __arm64_sys_io_submit+0x26c/0x3ec fs/aio.c:2063
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585