==================================================================
BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x5e0/0xb08 fs/reiserfs/lbalance.c:1043
Read of size 48 at addr ffff0000fbd24ff0 by task syz.2.94/4777

CPU: 1 PID: 4777 Comm: syz.2.94 Not tainted 6.1.134-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0x174/0x4c0 mm/kasan/report.c:427
 kasan_report+0xd4/0x130 mm/kasan/report.c:531
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:189
 memcpy+0x48/0x90 mm/kasan/shadow.c:65
 leaf_paste_in_buffer+0x5e0/0xb08 fs/reiserfs/lbalance.c:1043
 leaf_copy_dir_entries+0x2b0/0x9f8 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+0xa2c/0x1004 fs/reiserfs/lbalance.c:726
 balance_leaf_when_delete_left fs/reiserfs/do_balan.c:167 [inline]
 balance_leaf_when_delete fs/reiserfs/do_balan.c:272 [inline]
 balance_leaf+0xa2a4/0xe860 fs/reiserfs/do_balan.c:1393
 do_balance+0x27c/0x788 fs/reiserfs/do_balan.c:1888
 reiserfs_cut_from_item+0x12b8/0x1c98 fs/reiserfs/stree.c:1838
 reiserfs_do_truncate+0x89c/0x11c8 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x510/0xb1c fs/reiserfs/inode.c:2310
 reiserfs_setattr+0xb58/0x101c fs/reiserfs/inode.c:3395
 notify_change+0xb58/0xe1c fs/attr.c:499
 do_truncate+0x1c0/0x28c fs/open.c:65
 do_sys_ftruncate+0x288/0x31c fs/open.c:193
 __do_sys_ftruncate fs/open.c:204 [inline]
 __se_sys_ftruncate fs/open.c:202 [inline]
 __arm64_sys_ftruncate+0x60/0x74 fs/open.c:202
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the physical page:
page:0000000022d498b8 refcount:2 mapcount:0 mapping:00000000f43025d5 index:0x21c pfn:0x13bd24
memcg:ffff0000cb5ae000
aops:def_blk_aops ino:700002
flags: 0x5ffd60000002052(referenced|lru|workingset|private|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffd60000002052 fffffc0003ef48c8 fffffc0003858d48 ffff0000c049bf10
raw: 000000000000021c ffff0000f55f93a0 00000002ffffffff ffff0000cb5ae000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000fbd24f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000fbd24f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000fbd25000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff0000fbd25080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000fbd25100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
REISERFS error (device loop2): vs-4010 is_reusable: block number is out of range 11822 (1024)
REISERFS (device loop2): Remounting filesystem read-only
REISERFS warning (device loop2): clm-6006 reiserfs_dirty_inode: writing inode 5 on readonly FS