REISERFS (device loop0): using ordered data mode
reiserfs: using flush barriers
REISERFS (device loop0): journal params: device loop0, size 512, journal first block 18, max trans len 256, max batch 225, max commit age 30, max trans age 30
REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using r5 hash to sort names
==================================================================
BUG: KASAN: use-after-free in strlen+0x7d/0xa0 lib/string.c:418
Read of size 1 at addr ffff888072f6a7a3 by task syz-executor939/4996

CPU: 0 PID: 4996 Comm: syz-executor939 Not tainted 6.4.0-syzkaller-10098-g995b406c7e97 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:364
 print_report mm/kasan/report.c:475 [inline]
 kasan_report+0x11d/0x130 mm/kasan/report.c:588
 strlen+0x7d/0xa0 lib/string.c:418
 __fortify_strlen include/linux/fortify-string.h:214 [inline]
 set_de_name_and_namelen+0x4c4/0x6a0 fs/reiserfs/namei.c:82
 linear_search_in_dir_item fs/reiserfs/namei.c:262 [inline]
 reiserfs_find_entry.part.0+0x3db/0xdf0 fs/reiserfs/namei.c:331
 reiserfs_find_entry fs/reiserfs/namei.c:368 [inline]
 reiserfs_lookup+0x24e/0x610 fs/reiserfs/namei.c:368
 __lookup_slow+0x24c/0x460 fs/namei.c:1690
 lookup_one_len+0x16e/0x1a0 fs/namei.c:2742
 reiserfs_lookup_privroot+0x96/0x210 fs/reiserfs/xattr.c:976
 reiserfs_fill_super+0x1a8d/0x2eb0 fs/reiserfs/super.c:2192
 mount_bdev+0x315/0x3e0 fs/super.c:1391
 legacy_get_tree+0x109/0x220 fs/fs_context.c:611
 vfs_get_tree+0x8d/0x350 fs/super.c:1519
 do_new_mount fs/namespace.c:3335 [inline]
 path_mount+0x136e/0x1e70 fs/namespace.c:3662
 do_mount fs/namespace.c:3675 [inline]
 __do_sys_mount fs/namespace.c:3884 [inline]
 __se_sys_mount fs/namespace.c:3861 [inline]
 __x64_sys_mount+0x283/0x300 fs/namespace.c:3861
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f57c9065f8a
Code: 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd788538f8 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f57c9065f8a
RDX: 00000000200000c0 RSI: 0000000020000040 RDI: 00007ffd78853900
RBP: 00007ffd78853900 R08: 00007ffd78853940 R09: 000000000000111c
R10: 0000000000008001 R11: 0000000000000286 R12: 0000000000000004
R13: 0000555555ac52c0 R14: 00007ffd78853940 R15: 0000000000000000
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001cbda80 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x72f6a
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 ffffea0001cdd548 ffffea0001cdb288 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 4993, tgid 4993 (sshd), ts 44534955999, free_ts 44535825339
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2db/0x350 mm/page_alloc.c:1570
 prep_new_page mm/page_alloc.c:1577 [inline]
 get_page_from_freelist+0xfed/0x2d30 mm/page_alloc.c:3221
 __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:4477
 __folio_alloc+0x16/0x40 mm/page_alloc.c:4509
 vma_alloc_folio+0x155/0x890 mm/mempolicy.c:2240
 wp_page_copy mm/memory.c:3085 [inline]
 do_wp_page+0x867/0x37c0 mm/memory.c:3446
 handle_pte_fault mm/memory.c:4948 [inline]
 __handle_mm_fault+0x1573/0x3c50 mm/memory.c:5072
 handle_mm_fault+0x2a7/0x9e0 mm/memory.c:5226
 do_user_addr_fault+0x2dc/0x1360 arch/x86/mm/fault.c:1343
 handle_page_fault arch/x86/mm/fault.c:1486 [inline]
 exc_page_fault+0x98/0x170 arch/x86/mm/fault.c:1542
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1161 [inline]
 free_unref_page_prepare+0x62e/0xcb0 mm/page_alloc.c:2348
 free_unref_page_list+0xe3/0xa70 mm/page_alloc.c:2489
 release_pages+0xcd8/0x1380 mm/swap.c:1042
 tlb_batch_pages_flush+0xa8/0x1a0 mm/mmu_gather.c:97
 tlb_flush_mmu_free mm/mmu_gather.c:292 [inline]
 tlb_flush_mmu mm/mmu_gather.c:299 [inline]
 tlb_finish_mmu+0x14b/0x7e0 mm/mmu_gather.c:391
 unmap_region+0x23d/0x2d0 mm/mmap.c:2313
 do_vmi_align_munmap+0xdea/0x1680 mm/mmap.c:2552
 do_vmi_munmap+0x266/0x430 mm/mmap.c:2619
 __vm_munmap+0x137/0x380 mm/mmap.c:2899
 __do_sys_munmap mm/mmap.c:2916 [inline]
 __se_sys_munmap mm/mmap.c:2913 [inline]
 __x64_sys_munmap+0x62/0x80 mm/mmap.c:2913
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff888072f6a680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888072f6a700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888072f6a780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff888072f6a800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888072f6a880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================