loop4: detected capacity change from 0 to 1024
======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc5-syzkaller-00053-g8c2e52ebbe88 #0 Not tainted
------------------------------------------------------
syz.4.217/7584 is trying to acquire lock:
ffff888056169548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_get_block+0x39e/0x1530 fs/hfsplus/extents.c:260

but task is already holding lock:
ffff88807a87b0f8 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0x94/0x9b0 fs/hfsplus/bitmap.c:35

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&sbi->alloc_mutex){+.+.}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:747
       hfsplus_block_free+0xbe/0x550 fs/hfsplus/bitmap.c:182
       hfsplus_free_extents+0x176/0xae0 fs/hfsplus/extents.c:363
       hfsplus_file_truncate+0x736/0xb40 fs/hfsplus/extents.c:592
       hfsplus_setattr+0x1c4/0x270 fs/hfsplus/inode.c:264
       notify_change+0xb33/0xe40 fs/attr.c:552
       do_truncate+0x1a4/0x220 fs/open.c:68
       handle_truncate fs/namei.c:3517 [inline]
       do_open fs/namei.c:3900 [inline]
       path_openat+0x306c/0x3830 fs/namei.c:4055
       do_filp_open+0x1fa/0x410 fs/namei.c:4082
       do_sys_openat2+0x121/0x1c0 fs/open.c:1437
       do_sys_open fs/open.c:1452 [inline]
       __do_sys_open fs/open.c:1460 [inline]
       __se_sys_open fs/open.c:1456 [inline]
       __x64_sys_open+0x11e/0x150 fs/open.c:1456
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3168 [inline]
       check_prevs_add kernel/locking/lockdep.c:3287 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:747
       hfsplus_get_block+0x39e/0x1530 fs/hfsplus/extents.c:260
       block_read_full_folio+0x29c/0x830 fs/buffer.c:2427
       filemap_read_folio+0x114/0x380 mm/filemap.c:2412
       do_read_cache_folio+0x350/0x590 mm/filemap.c:3894
       do_read_cache_page mm/filemap.c:3960 [inline]
       read_cache_page+0x5d/0x170 mm/filemap.c:3969
       read_mapping_page include/linux/pagemap.h:966 [inline]
       hfsplus_block_allocate+0xe4/0x9b0 fs/hfsplus/bitmap.c:37
       hfsplus_file_extend+0xae3/0x1990 fs/hfsplus/extents.c:469
       hfsplus_get_block+0x411/0x1530 fs/hfsplus/extents.c:245
       __block_write_begin_int+0x6b2/0x1900 fs/buffer.c:2151
       block_write_begin fs/buffer.c:2262 [inline]
       cont_write_begin+0x789/0xb50 fs/buffer.c:2601
       hfsplus_write_begin+0x66/0xb0 fs/hfsplus/inode.c:46
       page_symlink+0x26f/0x430 fs/namei.c:5520
       hfsplus_symlink+0xca/0x260 fs/hfsplus/dir.c:449
       vfs_symlink+0x143/0x2f0 fs/namei.c:4739
       do_symlinkat+0x1b1/0x3f0 fs/namei.c:4765
       __do_sys_symlink fs/namei.c:4786 [inline]
       __se_sys_symlink fs/namei.c:4784 [inline]
       __x64_sys_symlink+0x7a/0x90 fs/namei.c:4784
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sbi->alloc_mutex);
                               lock(&HFSPLUS_I(inode)->extents_lock);
                               lock(&sbi->alloc_mutex);
  lock(&HFSPLUS_I(inode)->extents_lock);

 *** DEADLOCK ***

5 locks held by syz.4.217/7584:
 #0: ffff88802aa4a428 (sb_writers#26){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff888056169df8 (&type->i_mutex_dir_key#20/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:914 [inline]
 #1: ffff888056169df8 (&type->i_mutex_dir_key#20/1){+.+.}-{4:4}, at: filename_create+0x1f9/0x470 fs/namei.c:4148
 #2: ffff88807a87b198 (&sbi->vh_mutex){+.+.}-{4:4}, at: hfsplus_symlink+0x81/0x260 fs/hfsplus/dir.c:444
 #3: ffff88805616a2c8 (&hip->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x1fc/0x1990 fs/hfsplus/extents.c:458
 #4: ffff88807a87b0f8 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0x94/0x9b0 fs/hfsplus/bitmap.c:35

stack backtrace:
CPU: 1 UID: 0 PID: 7584 Comm: syz.4.217 Not tainted 6.16.0-rc5-syzkaller-00053-g8c2e52ebbe88 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2046
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3168 [inline]
 check_prevs_add kernel/locking/lockdep.c:3287 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
 __mutex_lock_common kernel/locking/mutex.c:602 [inline]
 __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:747
 hfsplus_get_block+0x39e/0x1530 fs/hfsplus/extents.c:260
 block_read_full_folio+0x29c/0x830 fs/buffer.c:2427
 filemap_read_folio+0x114/0x380 mm/filemap.c:2412
 do_read_cache_folio+0x350/0x590 mm/filemap.c:3894
 do_read_cache_page mm/filemap.c:3960 [inline]
 read_cache_page+0x5d/0x170 mm/filemap.c:3969
 read_mapping_page include/linux/pagemap.h:966 [inline]
 hfsplus_block_allocate+0xe4/0x9b0 fs/hfsplus/bitmap.c:37
 hfsplus_file_extend+0xae3/0x1990 fs/hfsplus/extents.c:469
 hfsplus_get_block+0x411/0x1530 fs/hfsplus/extents.c:245
 __block_write_begin_int+0x6b2/0x1900 fs/buffer.c:2151
 block_write_begin fs/buffer.c:2262 [inline]
 cont_write_begin+0x789/0xb50 fs/buffer.c:2601
 hfsplus_write_begin+0x66/0xb0 fs/hfsplus/inode.c:46
 page_symlink+0x26f/0x430 fs/namei.c:5520
 hfsplus_symlink+0xca/0x260 fs/hfsplus/dir.c:449
 vfs_symlink+0x143/0x2f0 fs/namei.c:4739
 do_symlinkat+0x1b1/0x3f0 fs/namei.c:4765
 __do_sys_symlink fs/namei.c:4786 [inline]
 __se_sys_symlink fs/namei.c:4784 [inline]
 __x64_sys_symlink+0x7a/0x90 fs/namei.c:4784
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f173998e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f17377f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007f1739bb5fa0 RCX: 00007f173998e929
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000200000000440
RBP: 00007f1739a10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1739bb5fa0 R15: 00007fff389ce1d8
 </TASK>