+ mm-mm_init-add-zone-mismatch-warning-during-page-init.patch added to mm-new branch

+ mm-mm_init-add-zone-mismatch-warning-during-page-init.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/mm_init: add zone mismatch warning during page init
has been added to the -mm mm-new branch.  Its filename is
     mm-mm_init-add-zone-mismatch-warning-during-page-init.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mm_init-add-zone-mismatch-warning-during-page-init.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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and is updated there most days

------------------------------------------------------
From: Muchun Song <muchun.song@linux.dev>
Subject: mm/mm_init: add zone mismatch warning during page init
Date: Tue, 29 Sep 2026 13:32:31 +0800

For vmemmap-optimized sections, tail struct pages may be backed by shared
vmemmap pages.  Those shared pages must carry the same page zone ID as the
struct pages initialized for the section.

Warn in __init_single_page() if the shared tail page has a different
page_zone_id(), which would indicate inconsistent initialization.

Link: https://lore.kernel.org/20260929053231.66085-7-songmuchun@bytedance.com
Signed-off-by: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Qi Zheng <qi.zheng@linux.dev>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <chleroy@kernel.org>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Cc: Shrikanth Hegde <sshegde@linux.ibm.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
---

 mm/mm_init.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/mm/mm_init.c~mm-mm_init-add-zone-mismatch-warning-during-page-init
+++ a/mm/mm_init.c
@@ -609,6 +609,9 @@ void __meminit __init_single_page(struct
 	if (!is_highmem_idx(zone))
 		set_page_address(page, __va(pfn << PAGE_SHIFT));
 #endif
+	VM_WARN_ON_ONCE(vmemmap_optimizable_order(pfn_to_section_compound_order(pfn)) &&
+			page_zone_id(page + VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES) !=
+			page_zone_id(page));
 }
 
 #ifdef CONFIG_NUMA
_

Patches currently in -mm which might be from muchun.song@linux.dev are

mm-sparse-vmemmap-factor-out-shared-vmemmap-tail-page-allocation.patch
mm-sparse-vmemmap-allocate-shared-tail-page-array-dynamically.patch
mm-sparse-vmemmap-introduce-config_vmemmap_optimization.patch
mm-sparse-vmemmap-open-code-init_compound_tail.patch
mm-sparse-vmemmap-prepare-dax-vmemmap-population-for-compound-page-orders.patch
mm-sparse-vmemmap-set-compound-page-order-for-device-dax.patch
mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages.patch
mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix.patch
mm-sparse-vmemmap-move-vmemmap-optimization-helpers-to-a-public-header.patch
powerpc-mm-switch-device-dax-to-shared-tail-vmemmap-pages.patch
mm-sparse-vmemmap-drop-the-extra-tail-page-from-device-dax-reservation.patch
mm-sparse-vmemmap-drop-unused-section_nr_vmemmap_pages-arguments.patch
documentation-mm-update-dax-vmemmap-deduplication-docs.patch
mm-sparse-vmemmap-drop-vmemmap_populate_dax.patch
mm-sparse-vmemmap-support-device-dax-in-common-vmemmap-path.patch
mm-sparse-vmemmap-drop-device-dax-specific-population-path.patch
mm-sparse-vmemmap-remove-the-unused-ptpfn-argument.patch
mm-sparse-vmemmap-open-code-vmemmap_populate_address.patch
mm-mm_init-add-zone-mismatch-warning-during-page-init.patch