loop7: detected capacity change from 0 to 1024
======================================================
WARNING: possible circular locking dependency detected
6.16.0-syzkaller-00857-gced1b9e0392d #0 Not tainted
------------------------------------------------------
syz.7.10364/30215 is trying to acquire lock:
ffff8880298022c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_get_block+0x272/0x9d0 fs/hfsplus/extents.c:260

but task is already holding lock:
ffff8880534000f8 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0xe5/0xa40 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}:
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
       hfsplus_block_free+0xdc/0x5f0 fs/hfsplus/bitmap.c:182
       hfsplus_free_extents+0x33b/0x490 fs/hfsplus/extents.c:360
       hfsplus_file_truncate+0x8da/0xb70 fs/hfsplus/extents.c:589
       hfsplus_delete_inode+0x18f/0x220 fs/hfsplus/inode.c:452
       hfsplus_unlink+0x581/0x7f0 fs/hfsplus/dir.c:405
       vfs_unlink+0x2fe/0x9b0 fs/namei.c:4586
       do_unlinkat+0x4c5/0x6a0 fs/namei.c:4650
       __do_sys_unlink fs/namei.c:4696 [inline]
       __se_sys_unlink fs/namei.c:4694 [inline]
       __x64_sys_unlink+0xc5/0x110 fs/namei.c:4694
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 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 kernel/locking/lockdep.c:3911 [inline]
       __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
       lock_acquire kernel/locking/lockdep.c:5871 [inline]
       lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
       hfsplus_get_block+0x272/0x9d0 fs/hfsplus/extents.c:260
       block_read_full_folio+0x457/0x850 fs/buffer.c:2420
       filemap_read_folio+0xc8/0x2a0 mm/filemap.c:2412
       do_read_cache_folio+0x263/0x5c0 mm/filemap.c:3923
       do_read_cache_page mm/filemap.c:3989 [inline]
       read_cache_page+0x5b/0x160 mm/filemap.c:3998
       read_mapping_page include/linux/pagemap.h:993 [inline]
       hfsplus_block_allocate+0x144/0xa40 fs/hfsplus/bitmap.c:37
       hfsplus_file_extend+0x459/0x10f0 fs/hfsplus/extents.c:466
       hfsplus_get_block+0x1a9/0x9d0 fs/hfsplus/extents.c:245
       __block_write_begin_int+0x4f4/0x16d0 fs/buffer.c:2145
       block_write_begin+0x9a/0x1d0 fs/buffer.c:2256
       cont_write_begin+0x61b/0x950 fs/buffer.c:2594
       hfsplus_write_begin+0x64/0x120 fs/hfsplus/inode.c:48
       page_symlink+0x3fc/0x4c0 fs/namei.c:5512
       hfsplus_symlink+0xd3/0x2b0 fs/hfsplus/dir.c:449
       vfs_symlink fs/namei.c:4730 [inline]
       vfs_symlink+0x403/0x680 fs/namei.c:4714
       do_symlinkat+0x261/0x310 fs/namei.c:4756
       __do_sys_symlink fs/namei.c:4777 [inline]
       __se_sys_symlink fs/namei.c:4775 [inline]
       __x64_sys_symlink+0x75/0x90 fs/namei.c:4775
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 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.7.10364/30215:
 #0: ffff88807d738428 (sb_writers#16){.+.+}-{0:0}, at: filename_create+0x10e/0x4a0 fs/namei.c:4132
 #1: ffff888029803238 (&type->i_mutex_dir_key#12/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:914 [inline]
 #1: ffff888029803238 (&type->i_mutex_dir_key#12/1){+.+.}-{4:4}, at: filename_create+0x1bb/0x4a0 fs/namei.c:4139
 #2: ffff888053400198 (&sbi->vh_mutex){+.+.}-{4:4}, at: hfsplus_symlink+0x7f/0x2b0 fs/hfsplus/dir.c:444
 #3: ffff888029804488 (&hip->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x1ca/0x10f0 fs/hfsplus/extents.c:455
 #4: ffff8880534000f8 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0xe5/0xa40 fs/hfsplus/bitmap.c:35

stack backtrace:
CPU: 1 UID: 0 PID: 30215 Comm: syz.7.10364 Not tainted 6.16.0-syzkaller-00857-gced1b9e0392d #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2046
 check_noncircular+0x14c/0x170 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 kernel/locking/lockdep.c:3911 [inline]
 __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
 lock_acquire kernel/locking/lockdep.c:5871 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
 __mutex_lock_common kernel/locking/mutex.c:602 [inline]
 __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
 hfsplus_get_block+0x272/0x9d0 fs/hfsplus/extents.c:260
 block_read_full_folio+0x457/0x850 fs/buffer.c:2420
 filemap_read_folio+0xc8/0x2a0 mm/filemap.c:2412
 do_read_cache_folio+0x263/0x5c0 mm/filemap.c:3923
 do_read_cache_page mm/filemap.c:3989 [inline]
 read_cache_page+0x5b/0x160 mm/filemap.c:3998
 read_mapping_page include/linux/pagemap.h:993 [inline]
 hfsplus_block_allocate+0x144/0xa40 fs/hfsplus/bitmap.c:37
 hfsplus_file_extend+0x459/0x10f0 fs/hfsplus/extents.c:466
 hfsplus_get_block+0x1a9/0x9d0 fs/hfsplus/extents.c:245
 __block_write_begin_int+0x4f4/0x16d0 fs/buffer.c:2145
 block_write_begin+0x9a/0x1d0 fs/buffer.c:2256
 cont_write_begin+0x61b/0x950 fs/buffer.c:2594
 hfsplus_write_begin+0x64/0x120 fs/hfsplus/inode.c:48
 page_symlink+0x3fc/0x4c0 fs/namei.c:5512
 hfsplus_symlink+0xd3/0x2b0 fs/hfsplus/dir.c:449
 vfs_symlink fs/namei.c:4730 [inline]
 vfs_symlink+0x403/0x680 fs/namei.c:4714
 do_symlinkat+0x261/0x310 fs/namei.c:4756
 __do_sys_symlink fs/namei.c:4777 [inline]
 __se_sys_symlink fs/namei.c:4775 [inline]
 __x64_sys_symlink+0x75/0x90 fs/namei.c:4775
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6ba398e9a9
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:00007f6ba4834038 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007f6ba3bb5fa0 RCX: 00007f6ba398e9a9
RDX: 0000000000000000 RSI: 0000200000000cc0 RDI: 0000200000000800
RBP: 00007f6ba3a10d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f6ba3bb5fa0 R15: 00007fff5af9bbe8
 </TASK>