syzbot

loop0: detected capacity change from 0 to 1024
======================================================
WARNING: possible circular locking dependency detected
6.12.0-rc7-syzkaller-00070-g0a9b9d17f3a7 #0 Not tainted
------------------------------------------------------
syz-executor116/5921 is trying to acquire lock:
ffff88807e31f0f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x9e/0x8c0 fs/hfsplus/bitmap.c:35

but task is already holding lock:
ffff88805d4758c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x21b/0x1b70 fs/hfsplus/extents.c:458

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}:
       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_cont_expand_simple+0x18f/0x2b0 fs/buffer.c:2473
       hfsplus_setattr+0x16d/0x270 fs/hfsplus/inode.c:258
       notify_change+0xbca/0xe90 fs/attr.c:503
       do_truncate fs/open.c:65 [inline]
       do_ftruncate+0x462/0x580 fs/open.c:181
       do_sys_ftruncate fs/open.c:199 [inline]
       __do_sys_ftruncate fs/open.c:207 [inline]
       __se_sys_ftruncate fs/open.c:205 [inline]
       __x64_sys_ftruncate+0x95/0xf0 fs/open.c:205
       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

-> #0 (&sbi->alloc_mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
       __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_block_allocate+0x9e/0x8c0 fs/hfsplus/bitmap.c:35
       hfsplus_file_extend+0xade/0x1b70 fs/hfsplus/extents.c:469
       hfsplus_bmap_reserve+0x105/0x4e0 fs/hfsplus/btree.c:358
       hfsplus_create_cat+0x1b0/0x1b70 fs/hfsplus/catalog.c:272
       hfsplus_fill_super+0x13ee/0x1ca0 fs/hfsplus/super.c:566
       mount_bdev+0x20a/0x2d0 fs/super.c:1693
       legacy_get_tree+0xee/0x190 fs/fs_context.c:662
       vfs_get_tree+0x90/0x2b0 fs/super.c:1814
       do_new_mount+0x2be/0xb40 fs/namespace.c:3507
       do_mount fs/namespace.c:3847 [inline]
       __do_sys_mount fs/namespace.c:4057 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
       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

other info that might help us debug this:

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

4 locks held by syz-executor116/5921:
 #0: ffff888143f980e0 (&type->s_umount_key#43/1){+.+.}-{3:3}, at: alloc_super+0x221/0x9d0 fs/super.c:344
 #1: ffff88807e31f198 (&sbi->vh_mutex){+.+.}-{3:3}, at: hfsplus_fill_super+0x1380/0x1ca0 fs/hfsplus/super.c:559
 #2: ffff8880316000b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x14a/0x1c0 fs/hfsplus/bfind.c:28
 #3: ffff88805d4758c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x21b/0x1b70 fs/hfsplus/extents.c:458

stack backtrace:
CPU: 1 UID: 0 PID: 5921 Comm: syz-executor116 Not tainted 6.12.0-rc7-syzkaller-00070-g0a9b9d17f3a7 #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_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
 __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_block_allocate+0x9e/0x8c0 fs/hfsplus/bitmap.c:35
 hfsplus_file_extend+0xade/0x1b70 fs/hfsplus/extents.c:469
 hfsplus_bmap_reserve+0x105/0x4e0 fs/hfsplus/btree.c:358
 hfsplus_create_cat+0x1b0/0x1b70 fs/hfsplus/catalog.c:272
 hfsplus_fill_super+0x13ee/0x1ca0 fs/hfsplus/super.c:566
 mount_bdev+0x20a/0x2d0 fs/super.c:1693
 legacy_get_tree+0xee/0x190 fs/fs_context.c:662
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3507
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
 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: 0033:0x7f59a0a5b76a
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:00007ffc479c28d8 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffc479c2930 RCX: 00007f59a0a5b76a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffc479c2930
RBP: 0000000020000100 R08: 00007ffc479c2970 R09: 00000000000006e7
R10: 000000000180000c R11: 0000000000000286 R12: 0000000020000000
R13: 00007ffc479c2970 R14: 00000000000006ed R15: 0000000020000900
 </TASK>