do_coredump (elf_core_dump) and vm_file

Hi, I had to debug a coredump for a user process. I found the entire /proc/<pid>/maps data in core file, except the file names (vma->vm_file) as part of core generated. I was surprised to see this vma->vm_file is not dumped into core. Infact this is very much needed to debug cores. Why is that vma->vm_file not dumped into coredump? Any inputs will be of great help Thanks, Sudharsan