==================================================================
BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x578/0x9f0
Read of size 48 at addr ffff0001284bdff0 by task syz-executor.5/11583

CPU: 1 PID: 11583 Comm: syz-executor.5 Not tainted 5.15.127-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description+0x7c/0x3f0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x174/0x1e4 mm/kasan/report.c:451
 kasan_check_range+0x274/0x2b4 mm/kasan/generic.c:189
 memcpy+0x90/0xe8 mm/kasan/shadow.c:65
 leaf_paste_in_buffer+0x578/0x9f0
 leaf_copy_dir_entries+0x2b4/0xa04 fs/reiserfs/lbalance.c:108
 leaf_copy_boundary_item+0x8c4/0x1a34 fs/reiserfs/lbalance.c:168
 leaf_copy_items fs/reiserfs/lbalance.c:551 [inline]
 leaf_move_items+0xa0c/0x1f7c fs/reiserfs/lbalance.c:726
 leaf_shift_left+0xc8/0x39c fs/reiserfs/lbalance.c:750
 balance_leaf_left fs/reiserfs/do_balan.c:616 [inline]
 balance_leaf+0x103c/0xe860 fs/reiserfs/do_balan.c:1409
 do_balance+0x27c/0x790 fs/reiserfs/do_balan.c:1888
 reiserfs_insert_item+0x940/0xa84 fs/reiserfs/stree.c:2261
 add_save_link+0x390/0x678 fs/reiserfs/super.c:495
 reiserfs_truncate_file+0x38c/0x6f0 fs/reiserfs/inode.c:2317
 reiserfs_setattr+0x8e8/0xd94 fs/reiserfs/inode.c:3409
 notify_change+0xac4/0xd60 fs/attr.c:488
 do_truncate+0x1c0/0x28c fs/open.c:65
 handle_truncate fs/namei.c:3195 [inline]
 do_open fs/namei.c:3542 [inline]
 path_openat+0x20e8/0x26f0 fs/namei.c:3672
 do_filp_open+0x1a8/0x3b4 fs/namei.c:3699
 do_sys_openat2+0x128/0x3d8 fs/open.c:1211
 do_sys_open fs/open.c:1227 [inline]
 __do_sys_openat fs/open.c:1243 [inline]
 __se_sys_openat fs/open.c:1238 [inline]
 __arm64_sys_openat+0x1f0/0x240 fs/open.c:1238
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

The buggy address belongs to the page:
page:000000003bcb36a5 refcount:2 mapcount:0 mapping:000000009ce73ad0 index:0x214 pfn:0x1684bd
memcg:ffff0000d88b0000
aops:def_blk_aops ino:700005
flags: 0x5ffc00000002032(referenced|lru|active|private|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000002032 fffffc0004b08548 fffffc0004a09c88 ffff0000c5079488
raw: 0000000000000214 ffff00012c734000 00000002ffffffff ffff0000d88b0000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0001284bdf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0001284bdf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0001284be000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff0001284be080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0001284be100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
REISERFS warning: reiserfs-5093 is_leaf: item entry count seems wrong *3.5*[2 4106497 0(1) DIR], item_len 35, item_location 3937, free_space(entry_count) 2
REISERFS error (device loop5): vs-5150 search_by_key: invalid format found in block 531. Fsck?
REISERFS (device loop5): Remounting filesystem read-only
REISERFS error (device loop5): vs-5657 reiserfs_do_truncate: i/o failure occurred trying to truncate [2 4106498 0xffffffff DIRECT]
REISERFS warning (device loop5): clm-6006 reiserfs_dirty_inode: writing inode 4106498 on readonly FS