Merge tag 'mm-hotfixes-stable-2026-03-09-16-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "15 hotfixes. 6 are cc:stable. 14 are for MM.

  Singletons, with one doubleton - please see the changelogs for details"

* tag 'mm-hotfixes-stable-2026-03-09-16-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  MAINTAINERS, mailmap: update email address for Lorenzo Stoakes
  mm/mmu_notifier: clean up mmu_notifier.h kernel-doc
  uaccess: correct kernel-doc parameter format
  mm/huge_memory: fix a folio_split() race condition with folio_try_get()
  MAINTAINERS: add co-maintainer and reviewer for SLAB ALLOCATOR
  MAINTAINERS: add RELAY entry
  memcg: fix slab accounting in refill_obj_stock() trylock path
  mm/hugetlb.c: use __pa() instead of virt_to_phys() in early bootmem alloc code
  zram: rename writeback_compressed device attr
  tools/testing: fix testing/vma and testing/radix-tree build
  Revert "ptdesc: remove references to folios from __pagetable_ctor() and pagetable_dtor()"
  mm/cma: move put_page_testzero() out of VM_WARN_ON in cma_release()
  mm/damon/core: clear walk_control on inactive context in damos_walk()
  mm: memfd_luo: always dirty all folios
  mm: memfd_luo: always make all folios uptodate

6 files changed, 65 insertions, 15 deletions

diff --git a/mm/cma.c b/mm/cma.c
index 94b5da468a7d..15cc0ae76c8e 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -1013,6 +1013,7 @@ bool cma_release(struct cma *cma, const struct page *pages,
 		 unsigned long count)
 {
 	struct cma_memrange *cmr;
+	unsigned long ret = 0;
 	unsigned long i, pfn;
 
 	cmr = find_cma_memrange(cma, pages, count);
@@ -1021,7 +1022,9 @@ bool cma_release(struct cma *cma, const struct page *pages,
 
 	pfn = page_to_pfn(pages);
 	for (i = 0; i < count; i++, pfn++)
-		VM_WARN_ON(!put_page_testzero(pfn_to_page(pfn)));
+		ret += !put_page_testzero(pfn_to_page(pfn));
+
+	WARN(ret, "%lu pages are still in use!\n", ret);
 
 	__cma_release_frozen(cma, cmr, pages, count);
 
diff --git a/mm/damon/core.c b/mm/damon/core.c
index adfc52fee9dc..c1d1091d307e 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1562,8 +1562,13 @@ int damos_walk(struct damon_ctx *ctx, struct damos_walk_control *control)
 	}
 	ctx->walk_control = control;
 	mutex_unlock(&ctx->walk_control_lock);
-	if (!damon_is_running(ctx))
+	if (!damon_is_running(ctx)) {
+		mutex_lock(&ctx->walk_control_lock);
+		if (ctx->walk_control == control)
+			ctx->walk_control = NULL;
+		mutex_unlock(&ctx->walk_control_lock);
 		return -EINVAL;
+	}
 	wait_for_completion(&control->completion);
 	if (control->canceled)
 		return -ECANCELED;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8e2746ea74ad..912c248a3f7e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3631,6 +3631,7 @@ static int __split_unmapped_folio(struct folio *folio, int new_order,
 	const bool is_anon = folio_test_anon(folio);
 	int old_order = folio_order(folio);
 	int start_order = split_type == SPLIT_TYPE_UNIFORM ? new_order : old_order - 1;
+	struct folio *old_folio = folio;
 	int split_order;
 
 	/*
@@ -3651,12 +3652,16 @@ static int __split_unmapped_folio(struct folio *folio, int new_order,
 			 * uniform split has xas_split_alloc() called before
 			 * irq is disabled to allocate enough memory, whereas
 			 * non-uniform split can handle ENOMEM.
+			 * Use the to-be-split folio, so that a parallel
+			 * folio_try_get() waits on it until xarray is updated
+			 * with after-split folios and the original one is
+			 * unfrozen.
 			 */
-			if (split_type == SPLIT_TYPE_UNIFORM)
-				xas_split(xas, folio, old_order);
-			else {
+			if (split_type == SPLIT_TYPE_UNIFORM) {
+				xas_split(xas, old_folio, old_order);
+			} else {
 				xas_set_order(xas, folio->index, split_order);
-				xas_try_split(xas, folio, old_order);
+				xas_try_split(xas, old_folio, old_order);
 				if (xas_error(xas))
 					return xas_error(xas);
 			}
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0beb6e22bc26..327eaa4074d3 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3101,7 +3101,7 @@ static __init void *alloc_bootmem(struct hstate *h, int nid, bool node_exact)
 			 * extract the actual node first.
 			 */
 			if (m)
-				listnode = early_pfn_to_nid(PHYS_PFN(virt_to_phys(m)));
+				listnode = early_pfn_to_nid(PHYS_PFN(__pa(m)));
 		}
 
 		if (m) {
@@ -3160,7 +3160,7 @@ found:
 	 * The head struct page is used to get folio information by the HugeTLB
 	 * subsystem like zone id and node id.
 	 */
-	memblock_reserved_mark_noinit(virt_to_phys((void *)m + PAGE_SIZE),
+	memblock_reserved_mark_noinit(__pa((void *)m + PAGE_SIZE),
 		huge_page_size(h) - PAGE_SIZE);
 
 	return 1;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a52da3a5e4fd..772bac21d155 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3086,7 +3086,7 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
 
 	if (!local_trylock(&obj_stock.lock)) {
 		if (pgdat)
-			mod_objcg_mlstate(objcg, pgdat, idx, nr_bytes);
+			mod_objcg_mlstate(objcg, pgdat, idx, nr_acct);
 		nr_pages = nr_bytes >> PAGE_SHIFT;
 		nr_bytes = nr_bytes & (PAGE_SIZE - 1);
 		atomic_add(nr_bytes, &objcg->nr_charged_bytes);
diff --git a/mm/memfd_luo.c b/mm/memfd_luo.c
index e485b828d173..b8edb9f981d7 100644
--- a/mm/memfd_luo.c
+++ b/mm/memfd_luo.c
@@ -146,19 +146,56 @@ static int memfd_luo_preserve_folios(struct file *file,
 	for (i = 0; i < nr_folios; i++) {
 		struct memfd_luo_folio_ser *pfolio = &folios_ser[i];
 		struct folio *folio = folios[i];
-		unsigned int flags = 0;
 
 		err = kho_preserve_folio(folio);
 		if (err)
 			goto err_unpreserve;
 
-		if (folio_test_dirty(folio))
-			flags |= MEMFD_LUO_FOLIO_DIRTY;
-		if (folio_test_uptodate(folio))
-			flags |= MEMFD_LUO_FOLIO_UPTODATE;
+		folio_lock(folio);
+
+		/*
+		 * A dirty folio is one which has been written to. A clean folio
+		 * is its opposite. Since a clean folio does not carry user
+		 * data, it can be freed by page reclaim under memory pressure.
+		 *
+		 * Saving the dirty flag at prepare() time doesn't work since it
+		 * can change later. Saving it at freeze() also won't work
+		 * because the dirty bit is normally synced at unmap and there
+		 * might still be a mapping of the file at freeze().
+		 *
+		 * To see why this is a problem, say a folio is clean at
+		 * preserve, but gets dirtied later. The pfolio flags will mark
+		 * it as clean. After retrieve, the next kernel might try to
+		 * reclaim this folio under memory pressure, losing user data.
+		 *
+		 * Unconditionally mark it dirty to avoid this problem. This
+		 * comes at the cost of making clean folios un-reclaimable after
+		 * live update.
+		 */
+		folio_mark_dirty(folio);
+
+		/*
+		 * If the folio is not uptodate, it was fallocated but never
+		 * used. Saving this flag at prepare() doesn't work since it
+		 * might change later when someone uses the folio.
+		 *
+		 * Since we have taken the performance penalty of allocating,
+		 * zeroing, and pinning all the folios in the holes, take a bit
+		 * more and zero all non-uptodate folios too.
+		 *
+		 * NOTE: For someone looking to improve preserve performance,
+		 * this is a good place to look.
+		 */
+		if (!folio_test_uptodate(folio)) {
+			folio_zero_range(folio, 0, folio_size(folio));
+			flush_dcache_folio(folio);
+			folio_mark_uptodate(folio);
+		}
+
+		folio_unlock(folio);
 
 		pfolio->pfn = folio_pfn(folio);
-		pfolio->flags = flags;
+		pfolio->flags = MEMFD_LUO_FOLIO_DIRTY | MEMFD_LUO_FOLIO_UPTODATE;
 		pfolio->index = folio->index;
 	}