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BUG: KASAN: use-after-free in strlen+0x53/0x60 lib/string.c:581
Read of size 1 at addr ffff888056624008 by task syz-executor/5100

CPU: 1 PID: 5100 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 strlen+0x53/0x60 lib/string.c:581
 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+0x27f/0x1300 fs/reiserfs/dir.c:98
 iterate_dir+0x218/0x560 fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0xf2/0x270 fs/readdir.c:354
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe5a85e4873
Code: c7 c0 e8 ff ff ff 64 c7 00 16 00 00 00 31 c0 eb 9e e8 81 9b fd ff 90 b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 c7 c2 e8 ff ff ff f7 d8
RSP: 002b:00007ffd0a0b4848 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 0000555571c21a30 RCX: 00007fe5a85e4873
RDX: 0000000000008000 RSI: 0000555571c21a60 RDI: 0000000000000005
RBP: 0000555571c21a60 R08: 00007fe5a8806cc0 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000293 R12: 0000555571c21a34
R13: ffffffffffffffe8 R14: 0000000000000010 R15: 00007ffd0a0b6af0
 </TASK>

The buggy address belongs to the page:
page:ffffea0001598900 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x100 pfn:0x56624
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001598a08 ffffea0001597c08 0000000000000000
raw: 0000000000000100 0000000000000002 00000000ffffff7f 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 0x1112c4a(GFP_NOFS|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL|__GFP_MOVABLE|__GFP_SKIP_KASAN_POISON), pid 4664, ts 71555243723, free_ts 111631009344
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5487
 __page_cache_alloc+0xce/0x440 mm/filemap.c:1022
 page_cache_ra_unbounded+0x25d/0x940 mm/readahead.c:216
 page_cache_async_readahead include/linux/pagemap.h:856 [inline]
 do_async_mmap_readahead mm/filemap.c:3023 [inline]
 filemap_fault+0x5fa/0x1370 mm/filemap.c:3079
 __do_fault+0x141/0x330 mm/memory.c:3928
 do_read_fault mm/memory.c:4264 [inline]
 do_fault mm/memory.c:4392 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x2985/0x4410 mm/memory.c:4883
 faultin_page mm/gup.c:976 [inline]
 __get_user_pages+0x94b/0x11e0 mm/gup.c:1197
 __get_user_pages_locked mm/gup.c:1382 [inline]
 get_dump_page+0x190/0x680 mm/gup.c:1838
 dump_user_range+0x54/0x340 fs/coredump.c:1013
 elf_core_dump+0x2fbd/0x3500 fs/binfmt_elf.c:2285
 do_coredump+0x14c7/0x2ac0 fs/coredump.c:894
 get_signal+0x40a/0x12c0 kernel/signal.c:2886
 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page_list+0x119/0x820 mm/page_alloc.c:3433
 release_pages+0x186c/0x1be0 mm/swap.c:963
 __pagevec_release+0x6d/0xe0 mm/swap.c:983
 pagevec_release include/linux/pagevec.h:81 [inline]
 __invalidate_mapping_pages+0x570/0x6b0 mm/truncate.c:509
 drop_pagecache_sb+0x19a/0x230 fs/drop_caches.c:39
 iterate_supers+0x11e/0x1d0 fs/super.c:718
 drop_caches_sysctl_handler+0x8e/0x160 fs/drop_caches.c:62
 proc_sys_call_handler+0x45e/0x6d0 fs/proc/proc_sysctl.c:588
 do_iter_readv_writev+0x47e/0x5f0 fs/read_write.c:-1
 do_iter_write+0x205/0x7b0 fs/read_write.c:855
 iter_file_splice_write+0x699/0xcc0 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0xe1/0x130 fs/splice.c:956
 splice_direct_to_actor+0x4ea/0xc10 fs/splice.c:902
 do_splice_direct+0x1d4/0x2f0 fs/splice.c:1008
 do_sendfile+0x5fc/0xeb0 fs/read_write.c:1249

Memory state around the buggy address:
 ffff888056623f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888056623f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888056624000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                      ^
 ffff888056624080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888056624100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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