False memory-leak reports via misaligned pointer store

Memory-leak detection failure in Linux kernel BPF percpu hash maps allows local users to trigger false unreferenced-object reports. htab_elem_set_ptr stores the percpu pointer at l->key + key_size, so a four-byte key leaves the eight-byte pointer only four-byte aligned and kmemleak's eight-byte scan misses it. Reproduction requires CONFIG_DEBUG_KMEMLEAK and retaining the map during the BPF selftest; the demonstrated consequence is a false kmemleak warning rather than an actual lost allocation.