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 bin_search_in_dir_item fs/reiserfs/namei.c:40 [inline]
BUG: KASAN: use-after-free in search_by_entry_key+0x597/0x1370 fs/reiserfs/namei.c:165
Read of size 4 at addr ffff88805b377754 by task syz.0.17/4431

CPU: 1 PID: 4431 Comm: syz.0.17 Not tainted 6.1.147-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x200 mm/kasan/report.c:418
 kasan_report+0x10b/0x140 mm/kasan/report.c:522
 bin_search_in_dir_item fs/reiserfs/namei.c:40 [inline]
 search_by_entry_key+0x597/0x1370 fs/reiserfs/namei.c:165
 reiserfs_find_entry+0x2ff/0x18e0 fs/reiserfs/namei.c:322
 reiserfs_lookup+0x1a7/0x420 fs/reiserfs/namei.c:368
 __lookup_slow+0x27d/0x3a0 fs/namei.c:1690
 lookup_one_len+0x18e/0x2c0 fs/namei.c:2740
 reiserfs_lookup_privroot+0x85/0x1e0 fs/reiserfs/xattr.c:973
 reiserfs_fill_super+0x16ef/0x2340 fs/reiserfs/super.c:2192
 mount_bdev+0x287/0x3c0 fs/super.c:1443
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:632
 vfs_get_tree+0x88/0x270 fs/super.c:1573
 do_new_mount+0x24a/0xa40 fs/namespace.c:3063
 do_mount fs/namespace.c:3406 [inline]
 __do_sys_mount fs/namespace.c:3614 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3591
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb56579038a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd4ebb0998 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffd4ebb0a20 RCX: 00007fb56579038a
RDX: 0000200000000000 RSI: 0000200000000440 RDI: 00007ffd4ebb09e0
RBP: 0000200000000000 R08: 00007ffd4ebb0a20 R09: 000000000120c081
R10: 000000000120c081 R11: 0000000000000246 R12: 0000200000000440
R13: 00007ffd4ebb09e0 R14: 0000000000001108 R15: 0000200000000900
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00016cddc0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x5b377
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00016ce348 ffffea0001abcf48 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 4288, tgid 4288 (udevd), ts 99571866337, free_ts 99637268565
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328
 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614
 __folio_alloc+0xe/0x30 mm/page_alloc.c:5646
 vma_alloc_folio+0x4a3/0x900 mm/mempolicy.c:2243
 alloc_page_vma include/linux/gfp.h:284 [inline]
 do_anonymous_page mm/memory.c:4191 [inline]
 handle_pte_fault mm/memory.c:5029 [inline]
 __handle_mm_fault mm/memory.c:5173 [inline]
 handle_mm_fault+0x2242/0x3e70 mm/memory.c:5294
 do_user_addr_fault+0x51f/0xb10 arch/x86/mm/fault.c:1340
 handle_page_fault arch/x86/mm/fault.c:1431 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3384
 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3525
 release_pages+0x1f92/0x2200 mm/swap.c:1035
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu+0xff/0x210 mm/mmu_gather.c:261
 tlb_finish_mmu+0xbd/0x1c0 mm/mmu_gather.c:361
 unmap_region+0x272/0x2c0 mm/mmap.c:2339
 do_mas_align_munmap+0xc57/0x1220 mm/mmap.c:2588
 do_mas_munmap+0x240/0x2b0 mm/mmap.c:2646
 __vm_munmap+0x18d/0x290 mm/mmap.c:2932
 __do_sys_munmap mm/mmap.c:2957 [inline]
 __se_sys_munmap mm/mmap.c:2954 [inline]
 __x64_sys_munmap+0x5c/0x70 mm/mmap.c:2954
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88805b377600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805b377680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805b377700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                 ^
 ffff88805b377780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805b377800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================