============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.6.210/7843 is trying to acquire lock:
ffff0000f8ab22c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_get_block+0x2d4/0x1244 fs/hfsplus/extents.c:260

but task is already holding lock:
ffff0000f8ab2988 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x1b8/0x1530 fs/hfsplus/extents.c:453

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.6.210/7843:
 #0: ffff0000d1148420 (sb_writers#21){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3111 [inline]
 #0: ffff0000d1148420 (sb_writers#21){.+.+}-{0:0}, at: vfs_writev+0x21c/0x7cc fs/read_write.c:1055
 #1: ffff0000f8ab2b78 (&sb->s_type->i_mutex_key#28){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
 #1: ffff0000f8ab2b78 (&sb->s_type->i_mutex_key#28){+.+.}-{4:4}, at: generic_file_write_iter+0xdc/0x47c mm/filemap.c:4382
 #2: ffff0000f8ab2988 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x1b8/0x1530 fs/hfsplus/extents.c:453
 #3: ffff0000c2f4f0f8 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0x94/0x91c fs/hfsplus/bitmap.c:35

stack backtrace:
CPU: 1 UID: 0 PID: 7843 Comm: syz.6.210 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 print_deadlock_bug+0x2e8/0x2f0 kernel/locking/lockdep.c:3041
 check_deadlock kernel/locking/lockdep.c:3093 [inline]
 validate_chain kernel/locking/lockdep.c:3895 [inline]
 __lock_acquire+0x2940/0x30a4 kernel/locking/lockdep.c:5237
 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
 __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598
 __mutex_lock kernel/locking/mutex.c:760 [inline]
 mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812
 hfsplus_get_block+0x2d4/0x1244 fs/hfsplus/extents.c:260
 block_read_full_folio+0x2ec/0x824 fs/buffer.c:2420
 hfsplus_read_folio+0x28/0x38 fs/hfsplus/inode.c:28
 filemap_read_folio+0xec/0x2f8 mm/filemap.c:2444
 do_read_cache_folio+0x364/0x5bc mm/filemap.c:4024
 do_read_cache_page mm/filemap.c:4090 [inline]
 read_cache_page+0x6c/0x160 mm/filemap.c:4099
 read_mapping_page include/linux/pagemap.h:993 [inline]
 hfsplus_block_allocate+0xe4/0x91c fs/hfsplus/bitmap.c:37
 hfsplus_file_extend+0x774/0x1530 fs/hfsplus/extents.c:464
 hfsplus_get_block+0x32c/0x1244 fs/hfsplus/extents.c:245
 __block_write_begin_int+0x53c/0x15e8 fs/buffer.c:2145
 block_write_begin fs/buffer.c:2256 [inline]
 cont_write_begin+0x62c/0x968 fs/buffer.c:2594
 hfsplus_write_begin+0x7c/0xc4 fs/hfsplus/inode.c:48
 cont_expand_zero fs/buffer.c:2522 [inline]
 cont_write_begin+0x26c/0x968 fs/buffer.c:2584
 hfsplus_write_begin+0x7c/0xc4 fs/hfsplus/inode.c:48
 generic_perform_write+0x244/0x7bc mm/filemap.c:4242
 __generic_file_write_iter+0xfc/0x204 mm/filemap.c:4359
 generic_file_write_iter+0x10c/0x47c mm/filemap.c:4385
 do_iter_readv_writev+0x4bc/0x720 fs/read_write.c:-1
 vfs_writev+0x29c/0x7cc fs/read_write.c:1057
 do_pwritev fs/read_write.c:1153 [inline]
 __do_sys_pwritev2 fs/read_write.c:1211 [inline]
 __se_sys_pwritev2 fs/read_write.c:1202 [inline]
 __arm64_sys_pwritev2+0x1bc/0x2cc fs/read_write.c:1202
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:746
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:765
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596