REISERFS (device loop5): Using r5 hash to sort names
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BUG: KASAN: out-of-bounds in leaf_paste_entries+0x794/0x1130 fs/reiserfs/lbalance.c:1377
Read of size 18446744073709551584 at addr ffff88805b05dfa4 by task syz.5.892/7765

CPU: 1 PID: 7765 Comm: syz.5.892 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x235/0x290 mm/kasan/generic.c:189
 memmove+0x25/0x60 mm/kasan/shadow.c:54
 leaf_paste_entries+0x794/0x1130 fs/reiserfs/lbalance.c:1377
 balance_leaf_finish_node_paste_dirent fs/reiserfs/do_balan.c:1295 [inline]
 balance_leaf_finish_node_paste fs/reiserfs/do_balan.c:1321 [inline]
 balance_leaf_finish_node fs/reiserfs/do_balan.c:1364 [inline]
 balance_leaf+0xb2e5/0x10ec0 fs/reiserfs/do_balan.c:1452
 do_balance+0x318/0x930 fs/reiserfs/do_balan.c:1888
 reiserfs_paste_into_item+0x6dd/0x810 fs/reiserfs/stree.c:2159
 reiserfs_add_entry+0xa42/0xe10 fs/reiserfs/namei.c:567
 reiserfs_mkdir+0x6bc/0x920 fs/reiserfs/namei.c:862
 xattr_mkdir fs/reiserfs/xattr.c:76 [inline]
 create_privroot fs/reiserfs/xattr.c:889 [inline]
 reiserfs_xattr_init+0x331/0x720 fs/reiserfs/xattr.c:1012
 reiserfs_fill_super+0x1fe6/0x2440 fs/reiserfs/super.c:2179
 mount_bdev+0x287/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 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: 0033:0x7f583138f20a
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f582f5e7e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f582f5e7ee0 RCX: 00007f583138f20a
RDX: 0000200000000000 RSI: 00002000000000c0 RDI: 00007f582f5e7ea0
RBP: 0000200000000000 R08: 00007f582f5e7ee0 R09: 0000000000008488
R10: 0000000000008488 R11: 0000000000000246 R12: 00002000000000c0
R13: 00007f582f5e7ea0 R14: 0000000000001111 R15: 00002000000001c0
 </TASK>

The buggy address belongs to the page:
page:ffffea00016c1740 refcount:2 mapcount:0 mapping:ffff888145cc9470 index:0x213 pfn:0x5b05d
memcg:ffff88807ca84000
aops:def_blk_aops ino:700005
flags: 0xfff00000002032(referenced|lru|active|private|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002032 ffffea0001aaea88 ffff88807ad2a030 ffff888145cc9470
raw: 0000000000000213 ffff8880616891d0 00000002ffffffff ffff88807ca84000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x108c48(GFP_NOFS|__GFP_NOFAIL|__GFP_HARDWALL|__GFP_MOVABLE), pid 7765, ts 318750521604, free_ts 318368437009
 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
 pagecache_get_page+0x9b6/0xf10 mm/filemap.c:1940
 find_or_create_page include/linux/pagemap.h:420 [inline]
 grow_dev_page fs/buffer.c:949 [inline]
 grow_buffers fs/buffer.c:1014 [inline]
 __getblk_slow fs/buffer.c:1041 [inline]
 __getblk_gfp+0x247/0xb60 fs/buffer.c:1336
 sb_getblk include/linux/buffer_head.h:361 [inline]
 search_by_key+0x46c/0x4470 fs/reiserfs/stree.c:672
 reiserfs_read_locked_inode+0x195/0x26b0 fs/reiserfs/inode.c:1557
 reiserfs_fill_super+0x12af/0x2440 fs/reiserfs/super.c:2075
 mount_bdev+0x287/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 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
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
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu+0xce/0x180 mm/mmu_gather.c:247
 zap_pte_range mm/memory.c:1456 [inline]
 zap_pmd_range mm/memory.c:1505 [inline]
 zap_pud_range mm/memory.c:1534 [inline]
 zap_p4d_range mm/memory.c:1555 [inline]
 unmap_page_range+0x207a/0x2500 mm/memory.c:1576
 unmap_vmas+0x131/0x250 mm/memory.c:1653
 exit_mmap+0x3b9/0x640 mm/mmap.c:3216
 __mmput+0x115/0x3b0 kernel/fork.c:1127
 exit_mm+0x588/0x6e0 kernel/exit.c:550
 do_exit+0x5a9/0x20c0 kernel/exit.c:870
 do_group_exit+0x12e/0x300 kernel/exit.c:997
 get_signal+0x6ca/0x12c0 kernel/signal.c:2900
 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
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307

Memory state around the buggy address:
 ffff88805b05de80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88805b05df00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88805b05df80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                               ^
 ffff88805b05e000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805b05e080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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