[Crash-utility] Re: [PATCH v2 10/13] mm/sparse: remove SECTION_MARKED_PRESENT
On 9/27/26 21:20, David Carlier wrote:
On Mon, Sep 21, 2026 at 09:59:02PM +0200, David Hildenbrand (Arm)
wrote:
> enum {
> - SECTION_MARKED_PRESENT_BIT,
> SECTION_HAS_MEM_MAP_BIT,
> SECTION_IS_ONLINE_BIT,
> SECTION_IS_EARLY_BIT,
Hi David,
Hi!
It seems dropping SECTION_MARKED_PRESENT_BIT shifts the other section flags down
one bit. crash hardcodes SECTION_HAS_MEM_MAP as (1UL << 1) in
pfn_to_map(), so it now tests SECTION_IS_ONLINE: offline and
ZONE_DEVICE sections no longer resolve to a struct page. makedumpfile
only checks bit 0 and is fine.
Thanks. To be expected when relying on kernel internals.
Which makes me wonder why makedumpfile
(https://github.com/makedumpfile/makedumpfile) not require any such information.
Keep bit 0 reserved, or export the bits via vmcoreinfo?
We could export it, or
crash can simply detect the change based on the kernel
version. I remember the latter was done in makedumpfile in the past (although we
export it).
I can send a separate patch to export it.
--
Cheers,
David