REISERFS warning (device loop1): vs-13060 reiserfs_update_sd_size: stat data of object [1 2 0x0 SD] (nlink == 1) not found (pos 2)
REISERFS (device loop1): Created .reiserfs_priv - reserved for xattr storage.
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BUG: KASAN: use-after-free in strlen+0x53/0x60 lib/string.c:502
Read of size 1 at addr ffff8880528da008 by task syz.1.2/4358

CPU: 1 PID: 4358 Comm: syz.1.2 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
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x220 mm/kasan/report.c:427
 kasan_report+0x10b/0x140 mm/kasan/report.c:531
 strlen+0x53/0x60 lib/string.c:502
 _Z16__fortify_strlenPKcU17pass_object_size1 include/linux/fortify-string.h:196 [inline]
 set_de_name_and_namelen fs/reiserfs/namei.c:82 [inline]
 search_by_entry_key+0xa84/0x1370 fs/reiserfs/namei.c:172
 reiserfs_readdir_inode+0x22c/0x1230 fs/reiserfs/dir.c:98
 iterate_dir+0x218/0x560 fs/readdir.c:-1
 __do_sys_getdents fs/readdir.c:286 [inline]
 __se_sys_getdents+0xe5/0x250 fs/readdir.c:271
 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: 0033:0x7fad11f8e969
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:00007fad12e00038 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007fad121b5fa0 RCX: 00007fad11f8e969
RDX: 0000000000009005 RSI: 0000200000000280 RDI: 0000000000000005
RBP: 00007fad12010ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fad121b5fa0 R15: 00007ffd655d9f08
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00014a3680 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x528da
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00014a36c8 ffffea00014a5948 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 4363, tgid 4359 (syz.4.6), ts 86497038309, free_ts 86998384921
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328
 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5606
 __folio_alloc+0xe/0x30 mm/page_alloc.c:5638
 vma_alloc_folio+0x4a3/0x900 mm/mempolicy.c:2243
 shmem_alloc_folio mm/shmem.c:1589 [inline]
 shmem_alloc_and_acct_folio+0x42e/0xb60 mm/shmem.c:1613
 shmem_get_folio_gfp+0x1361/0x3400 mm/shmem.c:1941
 shmem_fault+0x1be/0x7b0 mm/shmem.c:2156
 __do_fault+0x13b/0x4e0 mm/memory.c:4280
 do_shared_fault mm/memory.c:4686 [inline]
 do_fault mm/memory.c:4764 [inline]
 handle_pte_fault mm/memory.c:5031 [inline]
 __handle_mm_fault mm/memory.c:5173 [inline]
 handle_mm_fault+0x1a93/0x3e70 mm/memory.c:5294
 faultin_page mm/gup.c:1026 [inline]
 __get_user_pages+0x3ff/0xeb0 mm/gup.c:1250
 faultin_vma_page_range+0x1dc/0x270 mm/gup.c:1670
 madvise_populate mm/madvise.c:928 [inline]
 madvise_vma_behavior mm/madvise.c:1037 [inline]
 madvise_walk_vmas mm/madvise.c:1259 [inline]
 do_madvise+0x122a/0x33d0 mm/madvise.c:1438
 __do_sys_madvise mm/madvise.c:1451 [inline]
 __se_sys_madvise mm/madvise.c:1449 [inline]
 __x64_sys_madvise+0xa2/0xb0 mm/madvise.c:1449
 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
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3384
 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3525
 release_pages+0x1f92/0x2200 mm/swap.c:1035
 __pagevec_release+0x6d/0xe0 mm/swap.c:1055
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 shmem_undo_range+0x75b/0x2050 mm/shmem.c:946
 shmem_truncate_range mm/shmem.c:1062 [inline]
 shmem_evict_inode+0x248/0xa40 mm/shmem.c:1171
 evict+0x485/0x870 fs/inode.c:705
 __dentry_kill+0x431/0x650 fs/dcache.c:611
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xfa/0x1d0 fs/dcache.c:918
 __fput+0x5e0/0x920 fs/file_table.c:328
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x936/0x2400 kernel/exit.c:871
 do_group_exit+0x217/0x2d0 kernel/exit.c:1021
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871

Memory state around the buggy address:
 ffff8880528d9f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880528d9f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880528da000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                      ^
 ffff8880528da080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880528da100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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