[merged mm-stable] mm-sparse-fix-preinited-section_mem_map-clobbering-on-failure-path.patch removed from -mm tree

[merged mm-stable] mm-sparse-fix-preinited-section_mem_map-clobbering-on-failure-path.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/sparse: fix preinited section_mem_map clobbering on failure path
has been removed from the -mm tree.  Its filename was
     mm-sparse-fix-preinited-section_mem_map-clobbering-on-failure-path.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm/sparse: fix preinited section_mem_map clobbering on failure path
Date: Tue, 31 Mar 2026 19:37:24 +0800

sparse_init_nid() is careful to leave alone every section whose vmemmap
has already been set up by sparse_vmemmap_init_nid_early(); it only clears
section_mem_map for the rest:

        if (!preinited_vmemmap_section(ms))
                ms->section_mem_map = 0;

A leftover line after that conditional block

        ms->section_mem_map = 0;

was supposed to be deleted but was missed in the failure path, causing the
field to be overwritten for all sections when memory allocation fails,
effectively destroying the pre-initialization check.

Drop the stray assignment so that preinited sections retain their
already valid state.

Those pre-inited sections (HugeTLB pages) are not activated.  However,
such failures are extremely rare, so I don't see any major userspace
issues.

Link: https://lore.kernel.org/20260331113724.2080833-1-songmuchun@bytedance.com
Fixes: d65917c42373 ("mm/sparse: allow for alternate vmemmap section init at boot")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed by: Donet Tom <donettom@linux.ibm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/sparse.c |    1 -
 1 file changed, 1 deletion(-)

--- a/mm/sparse.c~mm-sparse-fix-preinited-section_mem_map-clobbering-on-failure-path
+++ a/mm/sparse.c
@@ -403,7 +403,6 @@ failed:
 		ms = __nr_to_section(pnum);
 		if (!preinited_vmemmap_section(ms))
 			ms->section_mem_map = 0;
-		ms->section_mem_map = 0;
 	}
 }
 
_

Patches currently in -mm which might be from songmuchun@bytedance.com are