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BUG: KASAN: use-after-free in set_de_name_and_namelen+0x592/0x6a0 fs/reiserfs/namei.c:81
Read of size 1 at addr ffff888082dd5e2a by task syz-executor.2/20676

CPU: 1 PID: 20676 Comm: syz-executor.2 Not tainted 6.7.0-rc3-syzkaller-00284-g815fb87b7530 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xc4/0x620 mm/kasan/report.c:475
 kasan_report+0xda/0x110 mm/kasan/report.c:588
 set_de_name_and_namelen+0x592/0x6a0 fs/reiserfs/namei.c:81
 linear_search_in_dir_item fs/reiserfs/namei.c:262 [inline]
 reiserfs_find_entry+0x481/0xe70 fs/reiserfs/namei.c:331
 reiserfs_lookup+0x1f5/0x690 fs/reiserfs/namei.c:368
 __lookup_slow+0x24d/0x450 fs/namei.c:1694
 lookup_one_len+0x17d/0x1b0 fs/namei.c:2746
 reiserfs_lookup_privroot+0x94/0x200 fs/reiserfs/xattr.c:977
 reiserfs_fill_super+0x20f9/0x3160 fs/reiserfs/super.c:2174
 mount_bdev+0x1f3/0x2e0 fs/super.c:1650
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x370 fs/super.c:1771
 do_new_mount fs/namespace.c:3337 [inline]
 path_mount+0x1492/0x1ed0 fs/namespace.c:3664
 do_mount fs/namespace.c:3677 [inline]
 __do_sys_mount fs/namespace.c:3886 [inline]
 __se_sys_mount fs/namespace.c:3863 [inline]
 __x64_sys_mount+0x293/0x310 fs/namespace.c:3863
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f7cc547e1ea
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:00007f7cc6168ee8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f7cc6168f80 RCX: 00007f7cc547e1ea
RDX: 0000000020000540 RSI: 0000000020000140 RDI: 00007f7cc6168f40
RBP: 0000000020000540 R08: 00007f7cc6168f80 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000140
R13: 00007f7cc6168f40 R14: 0000000000001121 R15: 0000000020000800
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00020b7540 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x1 pfn:0x82dd5
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffff7f(buddy)
raw: 00fff00000000000 ffffea0001d71548 ffffea00017b7d88 0000000000000000
raw: 0000000000000001 0000000000000000 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 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO), pid 20692, tgid 20692 (modprobe), ts 867402441302, free_ts 867561331652
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2d0/0x350 mm/page_alloc.c:1537
 prep_new_page mm/page_alloc.c:1544 [inline]
 get_page_from_freelist+0xa25/0x36d0 mm/page_alloc.c:3312
 __alloc_pages+0x22e/0x2420 mm/page_alloc.c:4568
 alloc_pages_mpol+0x258/0x5f0 mm/mempolicy.c:2133
 vma_alloc_folio+0xad/0x220 mm/mempolicy.c:2172
 do_anonymous_page mm/memory.c:4171 [inline]
 do_pte_missing mm/memory.c:3728 [inline]
 handle_pte_fault mm/memory.c:5038 [inline]
 __handle_mm_fault+0xe07/0x3d70 mm/memory.c:5179
 handle_mm_fault+0x47a/0xa10 mm/memory.c:5344
 do_user_addr_fault+0x30b/0x1000 arch/x86/mm/fault.c:1364
 handle_page_fault arch/x86/mm/fault.c:1505 [inline]
 exc_page_fault+0x5d/0xc0 arch/x86/mm/fault.c:1561
 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:1137 [inline]
 free_unref_page_prepare+0x4fa/0xaa0 mm/page_alloc.c:2347
 free_unref_page_list+0xe6/0xb40 mm/page_alloc.c:2533
 release_pages+0x32a/0x14f0 mm/swap.c:1042
 tlb_batch_pages_flush+0x9a/0x190 mm/mmu_gather.c:98
 tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
 tlb_flush_mmu mm/mmu_gather.c:300 [inline]
 tlb_finish_mmu+0x14b/0x6f0 mm/mmu_gather.c:392
 exit_mmap+0x38b/0xa70 mm/mmap.c:3321
 __mmput+0x12a/0x4d0 kernel/fork.c:1349
 mmput+0x62/0x70 kernel/fork.c:1371
 exit_mm kernel/exit.c:567 [inline]
 do_exit+0x9ad/0x2ae0 kernel/exit.c:858
 do_group_exit+0xd4/0x2a0 kernel/exit.c:1021
 __do_sys_exit_group kernel/exit.c:1032 [inline]
 __se_sys_exit_group kernel/exit.c:1030 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1030
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Memory state around the buggy address:
 ffff888082dd5d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888082dd5d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888082dd5e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                  ^
 ffff888082dd5e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888082dd5f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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