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BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x578/0x9f0
Read of size 48 at addr ffff0000eb698ff0 by task syz.5.464/6424

CPU: 1 PID: 6424 Comm: syz.5.464 Not tainted 5.15.176-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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_when_delete_left fs/reiserfs/do_balan.c:194 [inline]
 balance_leaf_when_delete fs/reiserfs/do_balan.c:272 [inline]
 balance_leaf+0x2a70/0xe860 fs/reiserfs/do_balan.c:1393
 do_balance+0x27c/0x790 fs/reiserfs/do_balan.c:1888
 reiserfs_delete_solid_item+0x8fc/0xee0 fs/reiserfs/stree.c:1462
 remove_save_link+0x260/0x460 fs/reiserfs/super.c:540
 reiserfs_truncate_file+0x4e0/0x6f0 fs/reiserfs/inode.c:2330
 reiserfs_setattr+0x8e8/0xd94 fs/reiserfs/inode.c:3409
 notify_change+0xa34/0xcf8 fs/attr.c:505
 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+0x98/0x2b8 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:608
 el0t_64_sync_handler+0x84/0xe4 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:00000000b9fe33f7 refcount:2 mapcount:0 mapping:00000000a16f34d6 index:0x219 pfn:0x12b698
memcg:ffff0000d504c000
aops:def_blk_aops ino:700005
flags: 0x5ffc00000002032(referenced|lru|active|private|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000002032 fffffc0003b003c8 ffff0000c289c030 ffff0000c0551488
raw: 0000000000000219 ffff0000e932de80 00000002ffffffff ffff0000d504c000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000eb698f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000eb698f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000eb699000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff0000eb699080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000eb699100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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