REISERFS (device loop5): Using r5 hash to sort names
REISERFS warning (device loop5): vs-13060 reiserfs_update_sd_size: stat data of object [1 2 0x0 SD] (nlink == 1) not found (pos 2)
REISERFS (device loop5): Created .reiserfs_priv - reserved for xattr storage.
==================================================================
BUG: KASAN: use-after-free in strlen+0x53/0x60 lib/string.c:502
Read of size 1 at addr ffff88804cb4c008 by task syz.5.219/5554

CPU: 0 PID: 5554 Comm: syz.5.219 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 strlen+0x53/0x60 lib/string.c:502
 __fortify_strlen 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: 0033:0x7f54fb98f749
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:00007f54fc7c1038 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007f54fbbe5fa0 RCX: 00007f54fb98f749
RDX: 000000000000002b RSI: 0000200000000080 RDI: 0000000000000006
RBP: 00007f54fba13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f54fbbe6038 R14: 00007f54fbbe5fa0 R15: 00007fff58b14998
 </TASK>

The buggy address belongs to the physical page:
page:ffffea000132d300 refcount:1 mapcount:1 mapping:0000000000000000 index:0x7f2de204f pfn:0x4cb4c
memcg:ffff88807758a000
anon flags: 0xfff800000a0014(uptodate|lru|mappedtodisk|swapbacked|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff800000a0014 ffffea000132d348 ffffea000132d488 ffff888076d96551
raw: 00000007f2de204f 0000000000000000 0000000100000000 ffff88807758a000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO), pid 5577, tgid 5575 (syz.1.223), ts 148038790687, free_ts 147688502900
 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:5614
 __folio_alloc+0xe/0x30 mm/page_alloc.c:5646
 vma_alloc_folio+0x4a3/0x900 mm/mempolicy.c:2243
 alloc_page_vma include/linux/gfp.h:284 [inline]
 do_anonymous_page mm/memory.c:4191 [inline]
 handle_pte_fault mm/memory.c:5029 [inline]
 __handle_mm_fault mm/memory.c:5173 [inline]
 handle_mm_fault+0x2237/0x3e60 mm/memory.c:5294
 do_user_addr_fault+0x51f/0xb10 arch/x86/mm/fault.c:1340
 handle_page_fault arch/x86/mm/fault.c:1431 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
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
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu+0xff/0x210 mm/mmu_gather.c:261
 tlb_finish_mmu+0xbd/0x1c0 mm/mmu_gather.c:361
 exit_mmap+0x343/0x8e0 mm/mmap.c:3262
 __mmput+0x118/0x3c0 kernel/fork.c:1200
 exit_mm+0x1e6/0x2c0 kernel/exit.c:565
 do_exit+0x8c1/0x2400 kernel/exit.c:867
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87

Memory state around the buggy address:
 ffff88804cb4bf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804cb4bf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88804cb4c000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                      ^
 ffff88804cb4c080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804cb4c100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================