Re: [PATCH] dump read-only anonymous memory in core files

[Linus Torvalds]

What about shared mappings (that test should be VM_MAYSHARE)?

My inclination would be to not dump them if they are backed by a file, 
even if the mmap is writable.

Also, the VM_WRITE test should possibly be VM_MAYWRITE, since the thing
could have been mprotect()'ed. Alternatively, we could really add a "this
mapping has been writable" flag (a kind of "sticky VM_WRITE" bit). It's
only mprotect that can do this, anyway.

Ehh?

Which would make the logic be something like

	/* Do not dump I/O mapped devices! -DaveM */
	if (vma->vm_flags & VM_IO)
		return 0;

	/* file-backed mapping? */
	if (vma->vm_file) {
		if (vma->vm_flags & VM_MAYSHARE)
			return 0;
		if (!(vma->vm_flags & VM_MAYWRITE))
			return 0;
	}

	return 1;

Hmm?

		Linus

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