syzbot

loop3: detected capacity change from 0 to 64
======================================================
WARNING: possible circular locking dependency detected
6.1.140-syzkaller #0 Not tainted
------------------------------------------------------
syz.3.773/8608 is trying to acquire lock:
ffff8880309327f8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xd7/0x1280 fs/hfs/extent.c:397

but task is already holding lock:
ffff8880665020b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x15b/0x1d0 fs/hfs/bfind.c:-1

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&tree->tree_lock/1){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
       hfs_find_init+0x15b/0x1d0 fs/hfs/bfind.c:-1
       hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
       hfs_get_block+0x518/0xbd0 fs/hfs/extent.c:366
       block_read_full_folio+0x3c9/0xed0 fs/buffer.c:2271
       filemap_read_folio+0x160/0x760 mm/filemap.c:2490
       do_read_cache_folio+0x2a0/0x760 mm/filemap.c:3627
       do_read_cache_page+0x32/0x220 mm/filemap.c:3669
       read_mapping_page include/linux/pagemap.h:791 [inline]
       __hfs_bnode_create+0x4a5/0x790 fs/hfs/bnode.c:296
       hfs_bnode_find+0x21e/0xcc0 fs/hfs/bnode.c:341
       hfs_brec_find+0x156/0x500 fs/hfs/bfind.c:126
       hfs_brec_read+0x20/0x100 fs/hfs/bfind.c:165
       hfs_cat_find_brec+0x159/0x3f0 fs/hfs/catalog.c:194
       hfs_fill_super+0xecc/0x1410 fs/hfs/super.c:419
       mount_bdev+0x287/0x3c0 fs/super.c:1443
       legacy_get_tree+0xe6/0x180 fs/fs_context.c:632
       vfs_get_tree+0x88/0x270 fs/super.c:1573
       do_new_mount+0x24a/0xa40 fs/namespace.c:3058
       do_mount fs/namespace.c:3401 [inline]
       __do_sys_mount fs/namespace.c:3609 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3586
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
       lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
       hfs_extend_file+0xd7/0x1280 fs/hfs/extent.c:397
       hfs_bmap_reserve+0x103/0x420 fs/hfs/btree.c:234
       __hfs_ext_write_extent+0x1fa/0x470 fs/hfs/extent.c:121
       __hfs_ext_cache_extent+0x6b/0x9b0 fs/hfs/extent.c:174
       hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
       hfs_extend_file+0x313/0x1280 fs/hfs/extent.c:401
       hfs_get_block+0x3d4/0xbd0 fs/hfs/extent.c:353
       get_more_blocks fs/direct-io.c:665 [inline]
       do_direct_IO fs/direct-io.c:953 [inline]
       __blockdev_direct_IO+0x16a9/0x3450 fs/direct-io.c:1266
       blockdev_direct_IO include/linux/fs.h:3342 [inline]
       hfs_direct_IO+0x119/0x220 fs/hfs/inode.c:138
       generic_file_direct_write+0x3be/0x660 mm/filemap.c:3770
       __generic_file_write_iter+0x1db/0x430 mm/filemap.c:3930
       generic_file_write_iter+0xab/0x2e0 mm/filemap.c:4006
       call_write_iter include/linux/fs.h:2265 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x44c/0x960 fs/read_write.c:584
       ksys_write+0x143/0x240 fs/read_write.c:637
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&tree->tree_lock/1);
                               lock(&HFS_I(tree->inode)->extents_lock);
                               lock(&tree->tree_lock/1);
  lock(&HFS_I(tree->inode)->extents_lock);

 *** DEADLOCK ***

5 locks held by syz.3.773/8608:
 #0: ffff888018a5e5e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1040
 #1: ffff88807db06460 (sb_writers#31){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580
 #2: ffff888030933d28 (&sb->s_type->i_mutex_key#39){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #2: ffff888030933d28 (&sb->s_type->i_mutex_key#39){+.+.}-{3:3}, at: generic_file_write_iter+0x7f/0x2e0 mm/filemap.c:4003
 #3: ffff888030933b78 (&HFS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xd7/0x1280 fs/hfs/extent.c:397
 #4: ffff8880665020b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x15b/0x1d0 fs/hfs/bfind.c:-1

stack backtrace:
CPU: 1 PID: 8608 Comm: syz.3.773 Not tainted 6.1.140-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
 hfs_extend_file+0xd7/0x1280 fs/hfs/extent.c:397
 hfs_bmap_reserve+0x103/0x420 fs/hfs/btree.c:234
 __hfs_ext_write_extent+0x1fa/0x470 fs/hfs/extent.c:121
 __hfs_ext_cache_extent+0x6b/0x9b0 fs/hfs/extent.c:174
 hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
 hfs_extend_file+0x313/0x1280 fs/hfs/extent.c:401
 hfs_get_block+0x3d4/0xbd0 fs/hfs/extent.c:353
 get_more_blocks fs/direct-io.c:665 [inline]
 do_direct_IO fs/direct-io.c:953 [inline]
 __blockdev_direct_IO+0x16a9/0x3450 fs/direct-io.c:1266
 blockdev_direct_IO include/linux/fs.h:3342 [inline]
 hfs_direct_IO+0x119/0x220 fs/hfs/inode.c:138
 generic_file_direct_write+0x3be/0x660 mm/filemap.c:3770
 __generic_file_write_iter+0x1db/0x430 mm/filemap.c:3930
 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:4006
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x44c/0x960 fs/read_write.c:584
 ksys_write+0x143/0x240 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa22818e969
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:00007fa228f1c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa2283b5fa0 RCX: 00007fa22818e969
RDX: 000000000006e000 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007fa228210ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fa2283b5fa0 R15: 00007ffccca6fdd8
 </TASK>