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BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x66c/0xa14 fs/reiserfs/lbalance.c:-1
Read of size 48 at addr ffff000103317ff0 by task syz.5.119/5556

CPU: 1 PID: 5556 Comm: syz.5.119 Not tainted 6.1.148-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0x100 mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x260/0x2a0 mm/kasan/generic.c:189
 memcpy+0x48/0x90 mm/kasan/shadow.c:65
 leaf_paste_in_buffer+0x66c/0xa14 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
 leaf_shift_left+0xc8/0x3ac 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+0x182c/0xd2f4 fs/reiserfs/do_balan.c:1393
 do_balance+0x260/0x774 fs/reiserfs/do_balan.c:1888
 reiserfs_cut_from_item+0x1184/0x1a58 fs/reiserfs/stree.c:1838
 reiserfs_do_truncate+0x738/0x1020 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x5c0/0xaf4 fs/reiserfs/inode.c:2310
 reiserfs_setattr+0xac4/0xf7c fs/reiserfs/inode.c:3395
 notify_change+0xb0c/0xdcc fs/attr.c:499
 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+0x98/0x2bc 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+0x58/0x138 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:000000006b62ef1e refcount:2 mapcount:0 mapping:00000000600cc5f9 index:0x214 pfn:0x143317
memcg:ffff0000d0b8a000
aops:def_blk_aops ino:700005
flags: 0x5ffd40000002052(referenced|lru|workingset|private|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffd40000002052 fffffc0003f4da08 fffffc0003f700c8 ffff0000c0487610
raw: 0000000000000214 ffff0000e2340bc8 00000002ffffffff ffff0000d0b8a000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff000103317f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff000103317f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff000103318000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff000103318080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff000103318100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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