syzbot

loop0: detected capacity change from 0 to 1024
============================================
WARNING: possible recursive locking detected
6.12.0-rc6-syzkaller-00272-gda4373fbcf00 #0 Not tainted
--------------------------------------------
syz-executor391/5828 is trying to acquire lock:
ffff88807d2a87c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_get_block+0x383/0x14f0 fs/hfsplus/extents.c:260

but task is already holding lock:
ffff88807d2a9548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x21b/0x1b70 fs/hfsplus/extents.c:458

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-executor391/5828:
 #0: ffff88807d630420 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2931 [inline]
 #0: ffff88807d630420 (sb_writers#9){.+.+}-{0:0}, at: vfs_writev+0x2d1/0xba0 fs/read_write.c:1062
 #1: ffff88807d2a9738 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
 #1: ffff88807d2a9738 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: generic_file_write_iter+0x82/0x310 mm/filemap.c:4178
 #2: ffff88807d2a9548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x21b/0x1b70 fs/hfsplus/extents.c:458
 #3: ffff8880226930f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x9e/0x8c0 fs/hfsplus/bitmap.c:35

stack backtrace:
CPU: 1 UID: 0 PID: 5828 Comm: syz-executor391 Not tainted 6.12.0-rc6-syzkaller-00272-gda4373fbcf00 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037
 check_deadlock kernel/locking/lockdep.c:3089 [inline]
 validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 hfsplus_get_block+0x383/0x14f0 fs/hfsplus/extents.c:260
 block_read_full_folio+0x418/0xcd0 fs/buffer.c:2401
 filemap_read_folio+0x14b/0x630 mm/filemap.c:2367
 do_read_cache_folio+0x3f5/0x850 mm/filemap.c:3825
 do_read_cache_page+0x30/0x200 mm/filemap.c:3891
 read_mapping_page include/linux/pagemap.h:1005 [inline]
 hfsplus_block_allocate+0xee/0x8c0 fs/hfsplus/bitmap.c:37
 hfsplus_file_extend+0xade/0x1b70 fs/hfsplus/extents.c:469
 hfsplus_get_block+0x406/0x14f0 fs/hfsplus/extents.c:245
 __block_write_begin_int+0x50c/0x1a70 fs/buffer.c:2121
 block_write_begin fs/buffer.c:2231 [inline]
 cont_write_begin+0x6e2/0x9d0 fs/buffer.c:2582
 hfsplus_write_begin+0x68/0xb0 fs/hfsplus/inode.c:46
 cont_expand_zero fs/buffer.c:2509 [inline]
 cont_write_begin+0x338/0x9d0 fs/buffer.c:2572
 hfsplus_write_begin+0x68/0xb0 fs/hfsplus/inode.c:46
 generic_perform_write+0x344/0x6d0 mm/filemap.c:4054
 generic_file_write_iter+0xae/0x310 mm/filemap.c:4181
 do_iter_readv_writev+0x600/0x880
 vfs_writev+0x376/0xba0 fs/read_write.c:1064
 do_pwritev fs/read_write.c:1165 [inline]
 __do_sys_pwritev2 fs/read_write.c:1224 [inline]
 __se_sys_pwritev2+0x1ca/0x2d0 fs/read_write.c:1215
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2020269739
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:00007ffde03a9238 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 0032656c69662f2e RCX: 00007f2020269739
RDX: 0000000000000001 RSI: 0000000020000100 RDI: 0000000000000004
RBP: 00007f20202dc610 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000