==================================================================
BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x650/0xa0c fs/reiserfs/lbalance.c:-1
Read of size 48 at addr ffff0000edcc1ff0 by task syz.3.75/4479

CPU: 0 PID: 4479 Comm: syz.3.75 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call trace:
 dump_backtrace+0x0/0x43c arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
 print_address_description+0x78/0x30c mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xec/0x15c mm/kasan/report.c:451
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x270/0x2b0 mm/kasan/generic.c:189
 memcpy+0x90/0xe8 mm/kasan/shadow.c:65
 leaf_paste_in_buffer+0x650/0xa0c fs/reiserfs/lbalance.c:-1
 leaf_copy_dir_entries+0x45c/0x788 fs/reiserfs/lbalance.c:108
 leaf_copy_boundary_item+0x888/0x19dc fs/reiserfs/lbalance.c:-1
 leaf_copy_items fs/reiserfs/lbalance.c:551 [inline]
 leaf_move_items+0x694/0xb9c 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+0x9298/0xd2f4 fs/reiserfs/do_balan.c:1393
 do_balance+0x260/0x778 fs/reiserfs/do_balan.c:1888
 reiserfs_cut_from_item+0x1184/0x1a44 fs/reiserfs/stree.c:1838
 reiserfs_do_truncate+0x738/0x1020 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x328/0x6e4 fs/reiserfs/inode.c:2318
 reiserfs_setattr+0x8c8/0xd70 fs/reiserfs/inode.c:3409
 notify_change+0xa08/0xcd8 fs/attr.c:505
 do_truncate+0x178/0x1f0 fs/open.c:65
 vfs_truncate+0x23c/0x2b0 fs/open.c:111
 do_sys_truncate+0xe8/0x1b0 fs/open.c:134
 __do_sys_truncate fs/open.c:146 [inline]
 __se_sys_truncate fs/open.c:144 [inline]
 __arm64_sys_truncate+0x5c/0x70 fs/open.c:144
 __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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

The buggy address belongs to the page:
page:00000000798310e8 refcount:2 mapcount:0 mapping:00000000accc98c3 index:0x29a pfn:0x12dcc1
memcg:ffff0000d7134000
aops:def_blk_aops ino:700003
flags: 0x5ffc00000002032(referenced|lru|active|private|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000002032 fffffc0003b73008 fffffc00037c4f88 ffff0000c51e5b08
raw: 000000000000029a ffff0000e98fe2b8 00000002ffffffff ffff0000d7134000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000edcc1f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000edcc1f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000edcc2000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff0000edcc2080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000edcc2100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
REISERFS error (device loop3): vs-4010 is_reusable: block number is out of range 11822 (1024)
REISERFS (device loop3): Remounting filesystem read-only
REISERFS error (device loop3): vs-4010 is_reusable: block number is out of range 265564 (1024)
REISERFS error (device loop3): vs-4010 is_reusable: block number is out of range 593252 (1024)
REISERFS error (device loop3): vs-4080 _reiserfs_free_block: block 1: bit already cleared
REISERFS warning (device loop3): clm-6006 reiserfs_dirty_inode: writing inode 5 on readonly FS