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BUG: KASAN: slab-use-after-free in configfs_dirent_is_ready+0x6d/0x70 fs/configfs/dir.c:363
Read of size 4 at addr ffff88802c94c5b8 by task syz.2.2166/12019

CPU: 0 UID: 0 PID: 12019 Comm: syz.2.2166 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 configfs_dirent_is_ready+0x6d/0x70 fs/configfs/dir.c:363
 create_link fs/configfs/symlink.c:85 [inline]
 configfs_symlink+0x616/0x1030 fs/configfs/symlink.c:199
 vfs_symlink+0x18b/0x330 fs/namei.c:5660
 filename_symlinkat+0x1cd/0x420 fs/namei.c:5685
 __do_sys_symlinkat fs/namei.c:5705 [inline]
 __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5700
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd7b959e0d9
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:00007fd7b77f6028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007fd7b9825fa0 RCX: 00007fd7b959e0d9
RDX: 0000200000000200 RSI: ffffffffffffff9c RDI: 00002000000001c0
RBP: 00007fd7b9635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd7b9826038 R14: 00007fd7b9825fa0 R15: 00007ffdbe3f8348
 </TASK>

Allocated by task 12019:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4584 [inline]
 slab_alloc_node mm/slub.c:4917 [inline]
 kmem_cache_alloc_noprof+0x355/0x650 mm/slub.c:4931
 configfs_new_dirent+0x59/0x470 fs/configfs/dir.c:193
 configfs_make_dirent fs/configfs/dir.c:259 [inline]
 configfs_create_dir fs/configfs/dir.c:304 [inline]
 configfs_attach_item+0xa1/0xd60 fs/configfs/dir.c:863
 configfs_attach_group+0x2a/0x370 fs/configfs/dir.c:898
 configfs_mkdir+0x6f0/0x9e0 fs/configfs/dir.c:1423
 vfs_mkdir+0x402/0x620 fs/namei.c:5276
 filename_mkdirat+0x289/0x520 fs/namei.c:5309
 __do_sys_mkdirat fs/namei.c:5330 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5327
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 12022:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x187/0x6c0 mm/slub.c:6504
 release_configfs_dirent fs/configfs/configfs_internal.h:139 [inline]
 configfs_put fs/configfs/configfs_internal.h:156 [inline]
 configfs_d_iput+0x209/0x270 fs/configfs/dir.c:63
 d_delete_notify include/linux/fsnotify.h:379 [inline]
 vfs_rmdir+0x24a/0x6b0 fs/namei.c:5394
 filename_rmdir+0x292/0x520 fs/namei.c:5438
 __do_sys_rmdir fs/namei.c:5461 [inline]
 __se_sys_rmdir+0x2e/0x140 fs/namei.c:5458
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802c94c580
 which belongs to the cache configfs_dir_cache of size 96
The buggy address is located 56 bytes inside of
 freed 96-byte region [ffff88802c94c580, ffff88802c94c5e0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802c94c800 pfn:0x2c94c
flags: 0x80000000000200(workingset|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000200 ffff88801c294b40 ffff88801e2de688 ffff88801e2de688
raw: ffff88802c94c800 0000000800200010 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 12019, tgid 12018 (syz.2.2166), ts 613761576664, free_ts 613755226724
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0x262a/0x26a0 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab+0x79/0x5e0 mm/slub.c:3380
 new_slab mm/slub.c:3426 [inline]
 refill_objects+0x2d8/0x350 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x330/0x690 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 kmem_cache_alloc_noprof+0x452/0x650 mm/slub.c:4931
 configfs_new_dirent+0x59/0x470 fs/configfs/dir.c:193
 configfs_make_dirent fs/configfs/dir.c:259 [inline]
 configfs_create_dir fs/configfs/dir.c:304 [inline]
 configfs_attach_item+0xa1/0xd60 fs/configfs/dir.c:863
 configfs_attach_group+0x2a/0x370 fs/configfs/dir.c:898
 configfs_mkdir+0x6f0/0x9e0 fs/configfs/dir.c:1423
 vfs_mkdir+0x402/0x620 fs/namei.c:5276
 filename_mkdirat+0x289/0x520 fs/namei.c:5309
 __do_sys_mkdirat fs/namei.c:5330 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5327
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 20 tgid 20 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x10e7/0x11c0 mm/page_alloc.c:2950
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core kernel/rcu/tree.c:2897 [inline]
 rcu_cpu_kthread+0x950/0x1480 kernel/rcu/tree.c:2985
 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88802c94c480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802c94c500: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff88802c94c580: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                                        ^
 ffff88802c94c600: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
 ffff88802c94c680: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
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