==================================================================
BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x578/0x9f0
Read of size 48 at addr ffff0001403e8ff0 by task syz-executor.2/19267

CPU: 0 PID: 19267 Comm: syz-executor.2 Not tainted 6.1.75-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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:284 [inline]
 print_report+0x174/0x4c0 mm/kasan/report.c:395
 kasan_report+0xd4/0x130 mm/kasan/report.c:495
 kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:189
 memcpy+0x48/0x90 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_insert_left fs/reiserfs/do_balan.c:339 [inline]
 balance_leaf_left fs/reiserfs/do_balan.c:611 [inline]
 balance_leaf+0x189c/0xe860 fs/reiserfs/do_balan.c:1409
 do_balance+0x27c/0x788 fs/reiserfs/do_balan.c:1888
 reiserfs_insert_item+0x940/0xa84 fs/reiserfs/stree.c:2261
 reiserfs_get_block+0x18c0/0x45d8 fs/reiserfs/inode.c:868
 __block_write_begin_int+0x340/0x13b4 fs/buffer.c:1991
 __block_write_begin+0x7c/0xa0 fs/buffer.c:2041
 reiserfs_write_begin+0x328/0x71c fs/reiserfs/inode.c:2775
 generic_cont_expand_simple+0x160/0x258 fs/buffer.c:2347
 reiserfs_setattr+0x5c8/0x101c fs/reiserfs/inode.c:3305
 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+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 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:00000000afa6f249 refcount:3 mapcount:0 mapping:0000000000718566 index:0x214 pfn:0x1803e8
memcg:ffff0000d34a2000
aops:def_blk_aops ino:700002
flags: 0x5ffc60000002042(referenced|workingset|private|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc60000002042 0000000000000000 dead000000000122 ffff0000c0496010
raw: 0000000000000214 ffff0000dfd73740 00000003ffffffff ffff0000d34a2000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0001403e8f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0001403e8f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0001403e9000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff0001403e9080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0001403e9100: 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 1 0(1) DIR], item_len 35, item_location 3937, free_space(entry_count) 2
REISERFS error (device loop2): vs-5150 search_by_key: invalid format found in block 531. Fsck?
REISERFS (device loop2): Remounting filesystem read-only
REISERFS error (device loop2): vs-13050 reiserfs_update_sd_size: i/o failure occurred trying to update [2 3 0x0 SD] stat data
REISERFS warning: reiserfs-5093 is_leaf: item entry count seems wrong *3.5*[2 1 0(1) DIR], item_len 35, item_location 3937, free_space(entry_count) 2
REISERFS error (device loop2): vs-5150 search_by_key: invalid format found in block 531. Fsck?
REISERFS error (device loop2): vs-13050 reiserfs_update_sd_size: i/o failure occurred trying to update [2 3 0x0 SD] stat data