Re: [PATCH 3/4] coredump: ELF-FDPIC: enable to omit anonymous shared memory

[David Howells <dhowells@redhat.com>]

Kawai, Hidehiro <hidehiro.kawai.ez@hitachi.com> wrote:

>  static int elf_fdpic_dump_segments(struct file *file, struct mm_struct *mm,
> -				   size_t *size, unsigned long *limit)
> +				   size_t *size, unsigned long *limit,
> +				   unsigned int omit_anon_shared)

Why are you passing it as an extra argument when you could just use
mm->coredump_omit_anon_shared here:

> +		if (!maydump(vma, omit_anon_shared))

And here:

> +		phdr.p_filesz = maydump(vma, omit_anon_shared) ? sz : 0;

Actually, I think I would just pass the mm pointer you have into maydump() and
let that dereference it here:

> +		if (omit_anon_shared) {

which would then be:

		if (mm->coredump_omit_anon_shared) {

Then the calls to maydump() would be:

		if (!maydump(vma, mm))

and:

		phdr.p_filesz = maydump(vma, current->mm) ? sz : 0;

I wouldn't worry, were I you, about the setting changing whilst it's being
used.  If you are worried about that, you can probably do some locking against
that.

David