+ mm-hugetlb_cma-fix-null-nodemask-dereference-in-hugetlb_cma_alloc_frozen_folio-v5.patch added to mm-hotfixes-unstable branch

The patch titled
     Subject: mm/hugetlb_cma: Fix null nodemask dereference in hugetlb_cma_alloc_frozen_folio
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-hugetlb_cma-fix-null-nodemask-dereference-in-hugetlb_cma_alloc_frozen_folio-v5.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb_cma-fix-null-nodemask-dereference-in-hugetlb_cma_alloc_frozen_folio-v5.patch

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

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------------------------------------------------------
From: Sourav Panda <[email protected]>
Subject: mm/hugetlb_cma: Fix null nodemask dereference in hugetlb_cma_alloc_frozen_folio
Date: Sun, 9 Aug 2026 04:32:50 +0000

Changes in v5:
- Replaced defaulting nodemask to &node_states[N_MEMORY] with safely reading
  cpuset_current_mems_allowed using a seqcount retry loop, ensuring fallback
  allocations comply with task hardwall cpusets as suggested by Usama Arif.

Link: https://lore.kernel.org/[email protected]
Fixes: eb02f14c4a2b ("mm/hugetlb: allow overcommitting gigantic hugepages")
Signed-off-by: Sourav Panda <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Frank van der Linden <[email protected]>
Cc: Greg Thelen <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Usama Arif <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 mm/hugetlb_cma.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

--- a/mm/hugetlb_cma.c~mm-hugetlb_cma-fix-null-nodemask-dereference-in-hugetlb_cma_alloc_frozen_folio-v5
+++ a/mm/hugetlb_cma.c
@@ -3,6 +3,7 @@
 #include <linux/mm.h>
 #include <linux/cma.h>
 #include <linux/compiler.h>
+#include <linux/cpuset.h>
 #include <linux/mm_inline.h>
 
 #include <asm/page.h>
@@ -30,12 +31,21 @@ struct folio *hugetlb_cma_alloc_frozen_f
 	int node;
 	struct folio *folio;
 	struct page *page = NULL;
+	nodemask_t local_node_mask;
 
 	if (!hugetlb_cma_size)
 		return NULL;
 
-	if (!nodemask)
-		nodemask = &node_states[N_MEMORY];
+	if (!nodemask) {
+		unsigned int cpuset_mems_cookie;
+
+		do {
+			cpuset_mems_cookie = read_mems_allowed_begin();
+			local_node_mask = cpuset_current_mems_allowed;
+		} while (read_mems_allowed_retry(cpuset_mems_cookie));
+
+		nodemask = &local_node_mask;
+	}
 
 	if (hugetlb_cma[nid] && node_isset(nid, *nodemask))
 		page = cma_alloc_frozen_compound(hugetlb_cma[nid], order);
_

Patches currently in -mm which might be from [email protected] are

mm-hugetlb_cma-fix-null-nodemask-dereference-in-hugetlb_cma_alloc_frozen_folio.patch
mm-hugetlb_cma-fix-null-nodemask-dereference-in-hugetlb_cma_alloc_frozen_folio-v5.patch
mm-hugetlb_cma-support-percentage-based-hugetlb_cma-reservation.patch