CDS checks for file truncation with this in filemap.cpp:
  if (is_static()) {
    // just checking the last region is sufficient since the archive is written
    // in sequential order
    size_t len = os::lseek(fd, 0, SEEK_END);
    FileMapRegion* si = space_at(MetaspaceShared::last_valid_region);
    // The last space might be empty
    if (si->file_offset() > len || len - si->file_offset() < si->used()) {
      fail_continue("The shared archive file has been truncated.");
      return false;
    }
  }

but when -XX:+UseSerialGC is used, the last_valid_region is empty so si->file_offset() == 0 and we didn't detect truncation. We should check all the regions instead. Also, this should be done for dynamic archive as well.