Re: [PATCH v1 0/2] mm/kdump: exclude reserved pages in dumps

[Vlastimil Babka <vbabka@suse.cz>]

On 07/20/2018 02:34 PM, David Hildenbrand wrote:
> Dumping tools (like makedumpfile) right now don't exclude reserved pages.
> So reserved pages might be access by dump tools although nobody except
> the owner should touch them.

Are you sure about that? Or maybe I understand wrong. Maybe it changed
recently, but IIRC pages that are backing memmap (struct pages) are also
PG_reserved. And you definitely do want those in the dump.

> This is relevant in virtual environments where we soon might want to
> report certain reserved pages to the hypervisor and they might no longer
> be accessible - what already was documented for reserved pages a long
> time ago ("might not even exist").
> 
> David Hildenbrand (2):
>   mm: clarify semantics of reserved pages
>   kdump: include PG_reserved value in VMCOREINFO
> 
>  include/linux/page-flags.h | 4 ++--
>  kernel/crash_core.c        | 1 +
>  2 files changed, 3 insertions(+), 2 deletions(-)
>