================================================================== BUG: KASAN: slab-use-after-free in configfs_dirent_is_ready+0x6b/0x70 fs/configfs/dir.c:363 Read of size 4 at addr ffff8880275175b8 by task syz.0.151/6427 CPU: 1 UID: 0 PID: 6427 Comm: syz.0.151 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 configfs_dirent_is_ready+0x6b/0x70 fs/configfs/dir.c:363 create_link fs/configfs/symlink.c:85 [inline] configfs_symlink+0x5c4/0x11f0 fs/configfs/symlink.c:199 vfs_symlink fs/namei.c:5794 [inline] vfs_symlink+0x178/0x4d0 fs/namei.c:5773 filename_symlinkat+0x2a6/0x560 fs/namei.c:5819 __do_sys_symlinkat fs/namei.c:5839 [inline] __se_sys_symlinkat fs/namei.c:5834 [inline] __x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5834 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f43f8f9e159 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f43f9e67028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 00007f43f9225fa0 RCX: 00007f43f8f9e159 RDX: 0000200000000200 RSI: ffffffffffffff9c RDI: 00002000000001c0 RBP: 00007f43f9035024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f43f9226038 R14: 00007f43f9225fa0 R15: 00007ffd6aea1558 Allocated by task 6427: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_noprof+0x269/0x6a0 mm/slub.c:5010 configfs_new_dirent+0x52/0x570 fs/configfs/dir.c:193 configfs_make_dirent+0x36/0x1a0 fs/configfs/dir.c:259 configfs_create_dir+0xbd/0x5c0 fs/configfs/dir.c:304 configfs_attach_item fs/configfs/dir.c:863 [inline] configfs_attach_group+0x2a/0x440 fs/configfs/dir.c:898 configfs_mkdir+0x657/0xd40 fs/configfs/dir.c:1423 vfs_mkdir+0x364/0x850 fs/namei.c:5410 filename_mkdirat+0x48b/0x5e0 fs/namei.c:5443 __do_sys_mkdirat fs/namei.c:5464 [inline] __se_sys_mkdirat fs/namei.c:5461 [inline] __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5461 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6430: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6499 [inline] kmem_cache_free+0x127/0x6c0 mm/slub.c:6626 release_configfs_dirent fs/configfs/configfs_internal.h:139 [inline] release_configfs_dirent fs/configfs/configfs_internal.h:134 [inline] configfs_put fs/configfs/configfs_internal.h:156 [inline] configfs_d_iput+0x20d/0x290 fs/configfs/dir.c:63 dentry_unlink_inode+0x265/0x470 fs/dcache.c:477 d_delete fs/dcache.c:2700 [inline] d_delete+0x213/0x280 fs/dcache.c:2687 d_delete_notify include/linux/fsnotify.h:379 [inline] vfs_rmdir fs/namei.c:5528 [inline] vfs_rmdir+0x4ab/0x8a0 fs/namei.c:5488 filename_rmdir+0x31a/0x5c0 fs/namei.c:5572 __do_sys_rmdir fs/namei.c:5595 [inline] __se_sys_rmdir fs/namei.c:5592 [inline] __x64_sys_rmdir+0x46/0x70 fs/namei.c:5592 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888027517580 which belongs to the cache configfs_dir_cache of size 96 The buggy address is located 56 bytes inside of freed 96-byte region [ffff888027517580, ffff8880275175e0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x27517 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff8881404fd140 dead000000000122 0000000000000000 raw: 0000000000000000 0000000200200020 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5978, tgid 5977 (syz.4.52), ts 87408486170 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab mm/slub.c:3462 [inline] new_slab+0xa9/0x6e0 mm/slub.c:3513 refill_objects+0xe3/0x410 mm/slub.c:7410 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] kmem_cache_alloc_noprof+0x4c4/0x6a0 mm/slub.c:5010 configfs_new_dirent+0x52/0x570 fs/configfs/dir.c:193 configfs_make_dirent+0x36/0x1a0 fs/configfs/dir.c:259 configfs_create_file+0xfe/0x180 fs/configfs/file.c:454 populate_attrs fs/configfs/dir.c:640 [inline] configfs_attach_item.part.0+0x147/0x4f0 fs/configfs/dir.c:865 configfs_attach_item fs/configfs/dir.c:927 [inline] configfs_attach_group+0x63/0x440 fs/configfs/dir.c:898 configfs_mkdir+0x657/0xd40 fs/configfs/dir.c:1423 vfs_mkdir+0x364/0x850 fs/namei.c:5410 filename_mkdirat+0x48b/0x5e0 fs/namei.c:5443 __do_sys_mkdirat fs/namei.c:5464 [inline] __se_sys_mkdirat fs/namei.c:5461 [inline] __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5461 page last free pid 5975 tgid 5975 ts 87367356025 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_noprof+0x269/0x6a0 mm/slub.c:5010 new_handle fs/jbd2/transaction.c:457 [inline] jbd2__journal_start+0x194/0x6b0 fs/jbd2/transaction.c:485 __ext4_journal_start_sb+0x314/0x610 fs/ext4/ext4_jbd2.c:122 __ext4_journal_start fs/ext4/ext4_jbd2.h:238 [inline] ext4_dirty_inode+0xa1/0x130 fs/ext4/inode.c:6728 __mark_inode_dirty+0x1f3/0x16e0 fs/fs-writeback.c:2729 generic_update_time fs/inode.c:2253 [inline] file_update_time_flags+0x49c/0x520 fs/inode.c:2483 ext4_page_mkwrite+0x324/0x1860 fs/ext4/inode.c:6897 do_page_mkwrite+0x17a/0x440 mm/memory.c:3816 do_shared_fault mm/memory.c:6076 [inline] do_fault+0x659/0x1830 mm/memory.c:6138 do_pte_missing mm/memory.c:4700 [inline] handle_pte_fault mm/memory.c:6558 [inline] __handle_mm_fault+0x150b/0x2f60 mm/memory.c:6707 handle_mm_fault+0x363/0xa20 mm/memory.c:6876 do_user_addr_fault+0x59c/0x12f0 arch/x86/mm/fault.c:1343 Memory state around the buggy address: ffff888027517480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888027517500: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff888027517580: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff888027517600: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc ffff888027517680: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc ==================================================================