loop0: detected capacity change from 0 to 1024
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.17/4353 is trying to acquire lock:
ffff888024e51488 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_get_block+0x38f/0x1520 fs/hfsplus/extents.c:260

but task is already holding lock:
ffff888024e52808 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1ca/0x1a40 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.0.17/4353:
 #0: ffff8880202ca460 (sb_writers#13){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #1: ffff888024e529b0 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
 #1: ffff888024e529b0 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: generic_file_write_iter+0x7e/0x1b0 mm/filemap.c:3941
 #2: ffff888024e52808 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1ca/0x1a40 fs/hfsplus/extents.c:455
 #3: ffff8880755798f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x92/0x8d0 fs/hfsplus/bitmap.c:35

stack backtrace:
CPU: 1 PID: 4353 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 check_deadlock kernel/locking/lockdep.c:3048 [inline]
 validate_chain kernel/locking/lockdep.c:3842 [inline]
 __lock_acquire+0x67eb/0x7d40 kernel/locking/lockdep.c:5120
 lock_acquire+0x19f/0x400 kernel/locking/lockdep.c:5737
 __mutex_lock_common+0x1e5/0x2400 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+0x38f/0x1520 fs/hfsplus/extents.c:260
 block_read_full_page+0x308/0xd20 fs/buffer.c:2290
 do_read_cache_page+0x882/0x1010 mm/filemap.c:-1
 read_mapping_page include/linux/pagemap.h:515 [inline]
 hfsplus_block_allocate+0xdc/0x8d0 fs/hfsplus/bitmap.c:37
 hfsplus_file_extend+0xb17/0x1a40 fs/hfsplus/extents.c:466
 hfsplus_get_block+0x41d/0x1520 fs/hfsplus/extents.c:245
 get_more_blocks fs/direct-io.c:673 [inline]
 do_direct_IO fs/direct-io.c:959 [inline]
 do_blockdev_direct_IO fs/direct-io.c:1276 [inline]
 __blockdev_direct_IO+0x142d/0x3b20 fs/direct-io.c:1368
 blockdev_direct_IO include/linux/fs.h:3378 [inline]
 hfsplus_direct_IO+0x204/0x350 fs/hfsplus/inode.c:170
 generic_file_direct_write+0x222/0x470 mm/filemap.c:3687
 __generic_file_write_iter+0x2b2/0x4e0 mm/filemap.c:3869
 generic_file_write_iter+0xa6/0x1b0 mm/filemap.c:3944
 call_write_iter include/linux/fs.h:2179 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x748/0xd70 fs/read_write.c:594
 ksys_write+0x153/0x260 fs/read_write.c:647
 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: 0033:0x7f36aded11d9
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:00007ffd00add3f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f36ae158fa0 RCX: 00007f36aded11d9
RDX: 000000000003fe00 RSI: 0000200000004200 RDI: 0000000000000004
RBP: 00007f36adf68888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f36ae158fac R14: 00007f36ae158fa0 R15: 00007f36ae158fa0
 </TASK>