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+0x54/0x60 lib/string.c:566
Read of size 1 at addr ffff88806ecfd1b3 by task syz-executor.0/4580

CPU: 1 PID: 4580 Comm: syz-executor.0 Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 print_address_description+0x63/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x16b/0x1c0 mm/kasan/report.c:451
 strlen+0x54/0x60 lib/string.c:566
 set_de_name_and_namelen fs/reiserfs/namei.c:82 [inline]
 search_by_entry_key+0xa7b/0x1380 fs/reiserfs/namei.c:172
 reiserfs_find_entry+0xf47/0x19b0 fs/reiserfs/namei.c:322
 reiserfs_lookup+0x1e6/0x4b0 fs/reiserfs/namei.c:368
 __lookup_slow+0x275/0x3d0 fs/namei.c:1663
 lookup_one_len+0x187/0x2d0 fs/namei.c:2718
 reiserfs_lookup_privroot+0x85/0x1e0 fs/reiserfs/xattr.c:980
 reiserfs_fill_super+0x191e/0x2690 fs/reiserfs/super.c:2196
 mount_bdev+0x2c9/0x3f0 fs/super.c:1400
 legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
 do_mount fs/namespace.c:3355 [inline]
 __do_sys_mount fs/namespace.c:3563 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f8998dff05a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 09 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f899817eee8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f899817ef80 RCX: 00007f8998dff05a
RDX: 0000000020000140 RSI: 0000000020000340 RDI: 00007f899817ef40
RBP: 0000000020000140 R08: 00007f899817ef80 R09: 000000000120c083
R10: 000000000120c083 R11: 0000000000000246 R12: 0000000020000340
R13: 00007f899817ef40 R14: 0000000000001120 R15: 0000000020000380
 </TASK>

The buggy address belongs to the page:
page:ffffea0001bb3f40 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x6ecfd
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001bb3f88 ffffea0001bb3f08 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 0x1100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 4581, ts 83815595994, free_ts 83819046439
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x3b78/0x3d40 mm/page_alloc.c:4192
 __alloc_pages+0x272/0x700 mm/page_alloc.c:5465
 alloc_pages_vma+0x39a/0x800 mm/mempolicy.c:2146
 do_anonymous_page mm/memory.c:3836 [inline]
 handle_pte_fault mm/memory.c:4646 [inline]
 __handle_mm_fault mm/memory.c:4783 [inline]
 handle_mm_fault+0x2f49/0x5960 mm/memory.c:4881
 do_user_addr_fault arch/x86/mm/fault.c:1357 [inline]
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x271/0x700 arch/x86/mm/fault.c:1501
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
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+0xc34/0xcf0 mm/page_alloc.c:3317
 free_unref_page_list+0x1f7/0x8e0 mm/page_alloc.c:3433
 release_pages+0x1bb9/0x1f40 mm/swap.c:963
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x177/0x320 mm/mmu_gather.c:338
 exit_mmap+0x3cd/0x620 mm/mmap.c:3206
 __mmput+0x112/0x3b0 kernel/fork.c:1127
 exit_mm+0x688/0x7f0 kernel/exit.c:550
 do_exit+0x626/0x2480 kernel/exit.c:861
 do_group_exit+0x144/0x310 kernel/exit.c:996
 __do_sys_exit_group kernel/exit.c:1007 [inline]
 __se_sys_exit_group kernel/exit.c:1005 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1005
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff88806ecfd080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806ecfd100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806ecfd180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                     ^
 ffff88806ecfd200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806ecfd280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================