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 tea hash to sort names
==================================================================
BUG: KASAN: use-after-free in bin_search_in_dir_item fs/reiserfs/namei.c:40 [inline]
BUG: KASAN: use-after-free in search_by_entry_key+0x80a/0x940 fs/reiserfs/namei.c:165
Read of size 4 at addr ffff88808ac96fc4 by task syz-executor.0/21495

CPU: 1 PID: 21495 Comm: syz-executor.0 Not tainted 6.6.0-rc6-syzkaller-00043-gdd72f9c7e512 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
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
 bin_search_in_dir_item fs/reiserfs/namei.c:40 [inline]
 search_by_entry_key+0x80a/0x940 fs/reiserfs/namei.c:165
 reiserfs_find_entry+0x1dc/0xe70 fs/reiserfs/namei.c:322
 reiserfs_lookup+0x1f5/0x690 fs/reiserfs/namei.c:368
 __lookup_slow+0x24d/0x450 fs/namei.c:1693
 lookup_one_len+0x17d/0x1b0 fs/namei.c:2745
 reiserfs_lookup_privroot+0x94/0x200 fs/reiserfs/xattr.c:977
 reiserfs_fill_super+0x20f9/0x3150 fs/reiserfs/super.c:2174
 mount_bdev+0x1f3/0x2e0 fs/super.c:1629
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x370 fs/super.c:1750
 do_new_mount fs/namespace.c:3335 [inline]
 path_mount+0x1492/0x1ed0 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+0x293/0x310 fs/namespace.c:3861
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f01b887e1ea
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:00007f01b96a7ee8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f01b96a7f80 RCX: 00007f01b887e1ea
RDX: 00000000200000c0 RSI: 0000000020000040 RDI: 00007f01b96a7f40
RBP: 00000000200000c0 R08: 00007f01b96a7f80 R09: 000000000000800c
R10: 000000000000800c R11: 0000000000000202 R12: 0000000020000040
R13: 00007f01b96a7f40 R14: 0000000000001121 R15: 0000000020000300
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00022b2580 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x8ac96
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 dead000000000100 dead000000000122 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 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO), pid 5254, tgid 5025 (syz-fuzzer), ts 454986867364, free_ts 551481426139
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0xee0/0x2f20 mm/page_alloc.c:3170
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4426
 __folio_alloc+0x16/0x40 mm/page_alloc.c:4458
 vma_alloc_folio+0x156/0x890 mm/mempolicy.c:2258
 do_anonymous_page mm/memory.c:4110 [inline]
 do_pte_missing mm/memory.c:3667 [inline]
 handle_pte_fault mm/memory.c:4978 [inline]
 __handle_mm_fault+0xe67/0x3e10 mm/memory.c:5119
 handle_mm_fault+0x478/0xa00 mm/memory.c:5284
 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+0x5c/0xd0 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:1136 [inline]
 free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2312
 free_unref_page_list+0xe6/0xb30 mm/page_alloc.c:2451
 release_pages+0x32a/0x14e0 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
 zap_page_range_single+0x383/0x4e0 mm/memory.c:1768
 madvise_dontneed_single_vma mm/madvise.c:825 [inline]
 madvise_dontneed_free mm/madvise.c:906 [inline]
 madvise_vma_behavior+0xbb2/0x1e50 mm/madvise.c:1045
 madvise_walk_vmas+0x1cf/0x2c0 mm/madvise.c:1270
 do_madvise+0x333/0x660 mm/madvise.c:1450
 __do_sys_madvise mm/madvise.c:1463 [inline]
 __se_sys_madvise mm/madvise.c:1461 [inline]
 __x64_sys_madvise+0xaa/0x110 mm/madvise.c:1461
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff88808ac96e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88808ac96f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88808ac96f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff88808ac97000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88808ac97080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================