loop8: detected capacity change from 0 to 64 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.8.1205/9816 is trying to acquire lock: ffff888079e480b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x15b/0x1d0 fs/hfs/bfind.c:-1 but task is already holding lock: ffff8880292ee8f8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_get_block+0x265/0xbd0 fs/hfs/extent.c:365 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}: __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 __block_write_begin_int+0x54b/0x1a70 fs/buffer.c:1991 __block_write_begin fs/buffer.c:2041 [inline] block_write_begin+0x96/0x1e0 fs/buffer.c:2102 cont_write_begin+0x5c4/0x7d0 fs/buffer.c:2456 hfs_write_begin+0x87/0xd0 fs/hfs/inode.c:58 cont_expand_zero fs/buffer.c:2383 [inline] cont_write_begin+0x2a9/0x7d0 fs/buffer.c:2446 hfs_write_begin+0x87/0xd0 fs/hfs/inode.c:58 hfs_file_truncate+0x18d/0x9b0 fs/hfs/extent.c:494 hfs_inode_setattr+0x4ab/0x6f0 fs/hfs/inode.c:659 notify_change+0xc74/0xf40 fs/attr.c:499 do_truncate+0x197/0x220 fs/open.c:65 do_sys_ftruncate+0x312/0x3c0 fs/open.c:193 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 (&tree->tree_lock/1){+.+.}-{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_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_btree_open+0x568/0x10b0 fs/hfs/btree.c:78 hfs_mdb_get+0x1366/0x2010 fs/hfs/mdb.c:204 hfs_fill_super+0xe0b/0x1410 fs/hfs/super.c:406 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:3069 do_mount fs/namespace.c:3412 [inline] __do_sys_mount fs/namespace.c:3620 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3597 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(&HFS_I(tree->inode)->extents_lock); lock(&tree->tree_lock/1); lock(&HFS_I(tree->inode)->extents_lock); lock(&tree->tree_lock/1); *** DEADLOCK *** 2 locks held by syz.8.1205/9816: #0: ffff8880640e20e0 (&type->s_umount_key#50/1){+.+.}-{3:3}, at: alloc_super+0x1fa/0x930 fs/super.c:228 #1: ffff8880292ee8f8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_get_block+0x265/0xbd0 fs/hfs/extent.c:365 stack backtrace: CPU: 1 PID: 9816 Comm: syz.8.1205 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: 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_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_btree_open+0x568/0x10b0 fs/hfs/btree.c:78 hfs_mdb_get+0x1366/0x2010 fs/hfs/mdb.c:204 hfs_fill_super+0xe0b/0x1410 fs/hfs/super.c:406 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:3069 do_mount fs/namespace.c:3412 [inline] __do_sys_mount fs/namespace.c:3620 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3597 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: 0033:0x7fa78739034a Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fa7881abe68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fa7881abef0 RCX: 00007fa78739034a RDX: 0000200000002c80 RSI: 0000200000000000 RDI: 00007fa7881abeb0 RBP: 0000200000002c80 R08: 00007fa7881abef0 R09: 0000000000214498 R10: 0000000000214498 R11: 0000000000000246 R12: 0000200000000000 R13: 00007fa7881abeb0 R14: 0000000000000290 R15: 0000200000002cc0 hfs: unable to open catalog tree hfs: can't find a HFS filesystem on dev loop8