syzbot

loop0: detected capacity change from 0 to 1024
============================================
WARNING: possible recursive locking detected
6.15.0-rc2-syzkaller-00400-g3088d26962e8 #0 Not tainted
--------------------------------------------
syz-executor171/5834 is trying to acquire lock:
ffff88807d279548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_get_block+0x385/0x14f0 fs/hfsplus/extents.c:260

but task is already holding lock:
ffff88807d2787c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x21d/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

5 locks held by syz-executor171/5834:
 #0: ffff8880357940e0 (&type->s_umount_key#42/1){+.+.}-{4:4}, at: alloc_super+0x221/0x9d0 fs/super.c:344
 #1: ffff88807b7cb998 (&sbi->vh_mutex){+.+.}-{4:4}, at: hfsplus_fill_super+0x13d0/0x1d50 fs/hfsplus/super.c:554
 #2: ffff88807d3000b0 (&tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x14f/0x1d0 fs/hfsplus/bfind.c:28
 #3: ffff88807d2787c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x21d/0x1b70 fs/hfsplus/extents.c:458
 #4: ffff88807b7cb8f8 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0x9e/0x8c0 fs/hfsplus/bitmap.c:35

stack backtrace:
CPU: 1 UID: 0 PID: 5834 Comm: syz-executor171 Not tainted 6.15.0-rc2-syzkaller-00400-g3088d26962e8 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_deadlock_bug+0x2be/0x2d0 kernel/locking/lockdep.c:3042
 check_deadlock kernel/locking/lockdep.c:3094 [inline]
 validate_chain+0x928/0x24e0 kernel/locking/lockdep.c:3896
 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
 __mutex_lock_common kernel/locking/mutex.c:601 [inline]
 __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
 hfsplus_get_block+0x385/0x14f0 fs/hfsplus/extents.c:260
 block_read_full_folio+0x2d3/0x850 fs/buffer.c:2392
 filemap_read_folio+0x14a/0x3b0 mm/filemap.c:2401
 do_read_cache_folio+0x373/0x5b0 mm/filemap.c:3885
 do_read_cache_page mm/filemap.c:3951 [inline]
 read_cache_page+0x5b/0x170 mm/filemap.c:3960
 read_mapping_page include/linux/pagemap.h:989 [inline]
 hfsplus_block_allocate+0xee/0x8c0 fs/hfsplus/bitmap.c:37
 hfsplus_file_extend+0xae0/0x1b70 fs/hfsplus/extents.c:469
 hfsplus_bmap_reserve+0x105/0x4e0 fs/hfsplus/btree.c:358
 hfsplus_create_cat+0x1d3/0x1bd0 fs/hfsplus/catalog.c:272
 hfsplus_fill_super+0x1452/0x1d50 fs/hfsplus/super.c:561
 get_tree_bdev_flags+0x490/0x5c0 fs/super.c:1636
 vfs_get_tree+0x90/0x2b0 fs/super.c:1759
 do_new_mount+0x2cf/0xb70 fs/namespace.c:3881
 do_mount fs/namespace.c:4221 [inline]
 __do_sys_mount fs/namespace.c:4432 [inline]
 __se_sys_mount+0x38c/0x400 fs/namespace.c:4409
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb601431dea
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007ffdc173f468 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffdc173f480 RCX: 00007fb601431dea
RDX: 0000200000000100 RSI: 0000200000002900 RDI: 00007ffdc173f480
RBP: 0000200000002900 R08: 00007ffdc173f4c0 R09: 00000000000006d2
R10: 0000000002000010 R11: 0000000000000286 R12: 0000200000000100
R13: 00007ffdc173f4c0 R14: 0000000000000003 R15: 0000000002000010
 </TASK>