Merge tag 'mm-hotfixes-stable-2025-09-01-17-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
"17 hotfixes. 13 are cc:stable and the remainder address post-6.16
issues or aren't considered necessary for -stable kernels. 11 of these
fixes are for MM.

This includes a three-patch series from Harry Yoo which fixes an
intermittent boot failure which can occur on x86 systems. And a
two-patch series from Alexander Gordeev which fixes a KASAN crash on
S390 systems"

* tag 'mm-hotfixes-stable-2025-09-01-17-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm: fix possible deadlock in kmemleak
x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings()
mm: introduce and use {pgd,p4d}_populate_kernel()
mm: move page table sync declarations to linux/pgtable.h
proc: fix missing pde_set_flags() for net proc files
mm: fix accounting of memmap pages
mm/damon/core: prevent unnecessary overflow in damos_set_effective_quota()
kexec: add KEXEC_FILE_NO_CMA as a legal flag
kasan: fix GCC mem-intrinsic prefix with sw tags
mm/kasan: avoid lazy MMU mode hazards
mm/kasan: fix vmalloc shadow memory (de-)population races
kunit: kasan_test: disable fortify string checker on kasan_strings() test
selftests/mm: fix FORCE_READ to read input value correctly
mm/userfaultfd: fix kmap_local LIFO ordering for CONFIG_HIGHPTE
ocfs2: prevent release journal inode after journal shutdown
rust: mm: mark VmaNew as transparent
of_numa: fix uninitialized memory nodes causing kernel panic

arch/x86/include/asm/pgtable_64_types.h

···
 #define pgtable_l5_enabled() cpu_feature_enabled(X86_FEATURE_LA57)
 #endif /* USE_EARLY_PGTABLE_L5 */
 
+#define ARCH_PAGE_TABLE_SYNC_MASK \
+	(pgtable_l5_enabled() ? PGTBL_PGD_MODIFIED : PGTBL_P4D_MODIFIED)
+
 extern unsigned int pgdir_shift;
 extern unsigned int ptrs_per_p4d;
 

arch/x86/mm/init_64.c

···
 }
 
 /*
+ * Make kernel mappings visible in all page tables in the system.
+ * This is necessary except when the init task populates kernel mappings
+ * during the boot process. In that case, all processes originating from
+ * the init task copies the kernel mappings, so there is no issue.
+ * Otherwise, missing synchronization could lead to kernel crashes due
+ * to missing page table entries for certain kernel mappings.
+ *
+ * Synchronization is performed at the top level, which is the PGD in
+ * 5-level paging systems. But in 4-level paging systems, however,
+ * pgd_populate() is a no-op, so synchronization is done at the P4D level.
+ * sync_global_pgds() handles this difference between paging levels.
+ */
+void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
+{
+	sync_global_pgds(start, end);
+}
+
+/*
  * NOTE: This function is marked __ref because it calls __init function
  * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
  */

drivers/of/of_numa.c

···
 			r = -EINVAL;
 		}
 
-		for (i = 0; !r && !of_address_to_resource(np, i, &rsrc); i++)
+		for (i = 0; !r && !of_address_to_resource(np, i, &rsrc); i++) {
 			r = numa_add_memblk(nid, rsrc.start, rsrc.end + 1);
+			if (!r)
+				node_set(nid, numa_nodes_parsed);
+		}
 
 		if (!i || r) {
 			of_node_put(np);

fs/ocfs2/inode.c

···
 	 * the journal is flushed before journal shutdown. Thus it is safe to
 	 * have inodes get cleaned up after journal shutdown.
 	 */
+	if (!osb->journal)
+		return;
+
 	jbd2_journal_release_jbd_inode(osb->journal->j_journal,
 				       &oi->ip_jinode);
 }

fs/proc/generic.c

···
 	.setattr	= proc_notify_change,
 };
 
+static void pde_set_flags(struct proc_dir_entry *pde)
+{
+	const struct proc_ops *proc_ops = pde->proc_ops;
+
+	if (!proc_ops)
+		return;
+
+	if (proc_ops->proc_flags & PROC_ENTRY_PERMANENT)
+		pde->flags |= PROC_ENTRY_PERMANENT;
+	if (proc_ops->proc_read_iter)
+		pde->flags |= PROC_ENTRY_proc_read_iter;
+#ifdef CONFIG_COMPAT
+	if (proc_ops->proc_compat_ioctl)
+		pde->flags |= PROC_ENTRY_proc_compat_ioctl;
+#endif
+	if (proc_ops->proc_lseek)
+		pde->flags |= PROC_ENTRY_proc_lseek;
+}
+
 /* returns the registered entry, or frees dp and returns NULL on failure */
 struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
 		struct proc_dir_entry *dp)
 {
 	if (proc_alloc_inum(&dp->low_ino))
 		goto out_free_entry;
+
+	pde_set_flags(dp);
 
 	write_lock(&proc_subdir_lock);
 	dp->parent = dir;
···
 	return p;
 }
 
-static void pde_set_flags(struct proc_dir_entry *pde)
-{
-	if (pde->proc_ops->proc_flags & PROC_ENTRY_PERMANENT)
-		pde->flags |= PROC_ENTRY_PERMANENT;
-	if (pde->proc_ops->proc_read_iter)
-		pde->flags |= PROC_ENTRY_proc_read_iter;
-#ifdef CONFIG_COMPAT
-	if (pde->proc_ops->proc_compat_ioctl)
-		pde->flags |= PROC_ENTRY_proc_compat_ioctl;
-#endif
-	if (pde->proc_ops->proc_lseek)
-		pde->flags |= PROC_ENTRY_proc_lseek;
-}
-
 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
 		struct proc_dir_entry *parent,
 		const struct proc_ops *proc_ops, void *data)
···
 	if (!p)
 		return NULL;
 	p->proc_ops = proc_ops;
-	pde_set_flags(p);
 	return proc_register(parent, p);
 }
 EXPORT_SYMBOL(proc_create_data);
···
 	p->proc_ops = &proc_seq_ops;
 	p->seq_ops = ops;
 	p->state_size = state_size;
-	pde_set_flags(p);
 	return proc_register(parent, p);
 }
 EXPORT_SYMBOL(proc_create_seq_private);
···
 		return NULL;
 	p->proc_ops = &proc_single_ops;
 	p->single_show = show;
-	pde_set_flags(p);
 	return proc_register(parent, p);
 }
 EXPORT_SYMBOL(proc_create_single_data);

include/linux/kexec.h

···
 
 /* List of defined/legal kexec file flags */
 #define KEXEC_FILE_FLAGS	(KEXEC_FILE_UNLOAD | KEXEC_FILE_ON_CRASH | \
-				 KEXEC_FILE_NO_INITRAMFS | KEXEC_FILE_DEBUG)
+				 KEXEC_FILE_NO_INITRAMFS | KEXEC_FILE_DEBUG | \
+				 KEXEC_FILE_NO_CMA)
 
 /* flag to track if kexec reboot is in progress */
 extern bool kexec_in_progress;

include/linux/pgalloc.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_PGALLOC_H
+#define _LINUX_PGALLOC_H
+
+#include <linux/pgtable.h>
+#include <asm/pgalloc.h>
+
+/*
+ * {pgd,p4d}_populate_kernel() are defined as macros to allow
+ * compile-time optimization based on the configured page table levels.
+ * Without this, linking may fail because callers (e.g., KASAN) may rely
+ * on calls to these functions being optimized away when passing symbols
+ * that exist only for certain page table levels.
+ */
+#define pgd_populate_kernel(addr, pgd, p4d)				\
+	do {								\
+		pgd_populate(&init_mm, pgd, p4d);			\
+		if (ARCH_PAGE_TABLE_SYNC_MASK & PGTBL_PGD_MODIFIED)	\
+			arch_sync_kernel_mappings(addr, addr);		\
+	} while (0)
+
+#define p4d_populate_kernel(addr, p4d, pud)				\
+	do {								\
+		p4d_populate(&init_mm, p4d, pud);			\
+		if (ARCH_PAGE_TABLE_SYNC_MASK & PGTBL_P4D_MODIFIED)	\
+			arch_sync_kernel_mappings(addr, addr);		\
+	} while (0)
+
+#endif /* _LINUX_PGALLOC_H */

include/linux/pgtable.h

···
 }
 #endif
 
+/*
+ * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
+ * and let generic vmalloc, ioremap and page table update code know when
+ * arch_sync_kernel_mappings() needs to be called.
+ */
+#ifndef ARCH_PAGE_TABLE_SYNC_MASK
+#define ARCH_PAGE_TABLE_SYNC_MASK 0
+#endif
+
+/*
+ * There is no default implementation for arch_sync_kernel_mappings(). It is
+ * relied upon the compiler to optimize calls out if ARCH_PAGE_TABLE_SYNC_MASK
+ * is 0.
+ */
+void arch_sync_kernel_mappings(unsigned long start, unsigned long end);
+
 #endif /* CONFIG_MMU */
 
 /*
···
 /*
  * Page Table Modification bits for pgtbl_mod_mask.
  *
- * These are used by the p?d_alloc_track*() set of functions an in the generic
- * vmalloc/ioremap code to track at which page-table levels entries have been
- * modified. Based on that the code can better decide when vmalloc and ioremap
- * mapping changes need to be synchronized to other page-tables in the system.
+ * These are used by the p?d_alloc_track*() and p*d_populate_kernel()
+ * functions in the generic vmalloc, ioremap and page table update code
+ * to track at which page-table levels entries have been modified.
+ * Based on that the code can better decide when page table changes need
+ * to be synchronized to other page-tables in the system.
  */
 #define		__PGTBL_PGD_MODIFIED	0
 #define		__PGTBL_P4D_MODIFIED	1

include/linux/vmalloc.h

···
 		     struct page **pages, unsigned int page_shift);
 
 /*
- * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
- * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
- * needs to be called.
- */
-#ifndef ARCH_PAGE_TABLE_SYNC_MASK
-#define ARCH_PAGE_TABLE_SYNC_MASK 0
-#endif
-
-/*
- * There is no default implementation for arch_sync_kernel_mappings(). It is
- * relied upon the compiler to optimize calls out if ARCH_PAGE_TABLE_SYNC_MASK
- * is 0.
- */
-void arch_sync_kernel_mappings(unsigned long start, unsigned long end);
-
-/*
  *	Lowlevel-APIs (not for driver use!)
  */
 

mm/damon/core.c

···
 
 	if (quota->ms) {
 		if (quota->total_charged_ns)
-			throughput = quota->total_charged_sz * 1000000 /
-				quota->total_charged_ns;
+			throughput = mult_frac(quota->total_charged_sz, 1000000,
+							quota->total_charged_ns);
 		else
 			throughput = PAGE_SIZE * 1024;
 		esz = min(throughput * quota->ms, esz);

mm/kasan/init.c

···
 #include <linux/mm.h>
 #include <linux/pfn.h>
 #include <linux/slab.h>
+#include <linux/pgalloc.h>
 
 #include <asm/page.h>
-#include <asm/pgalloc.h>
 
 #include "kasan.h"
 
···
 			pud_t *pud;
 			pmd_t *pmd;
 
-			p4d_populate(&init_mm, p4d,
+			p4d_populate_kernel(addr, p4d,
 					lm_alias(kasan_early_shadow_pud));
 			pud = pud_offset(p4d, addr);
 			pud_populate(&init_mm, pud,
···
 			} else {
 				p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
 				pud_init(p);
-				p4d_populate(&init_mm, p4d, p);
+				p4d_populate_kernel(addr, p4d, p);
 			}
 		}
 		zero_pud_populate(p4d, addr, next);
···
 			 * puds,pmds, so pgd_populate(), pud_populate()
 			 * is noops.
 			 */
-			pgd_populate(&init_mm, pgd,
+			pgd_populate_kernel(addr, pgd,
 					lm_alias(kasan_early_shadow_p4d));
 			p4d = p4d_offset(pgd, addr);
-			p4d_populate(&init_mm, p4d,
+			p4d_populate_kernel(addr, p4d,
 					lm_alias(kasan_early_shadow_pud));
 			pud = pud_offset(p4d, addr);
 			pud_populate(&init_mm, pud,
···
 				if (!p)
 					return -ENOMEM;
 			} else {
-				pgd_populate(&init_mm, pgd,
+				pgd_populate_kernel(addr, pgd,
 					early_alloc(PAGE_SIZE, NUMA_NO_NODE));
 			}
 		}

mm/kasan/kasan_test_c.c

···
 
 	ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+	OPTIMIZER_HIDE_VAR(ptr);
 
 	src = kmalloc(KASAN_GRANULE_SIZE, GFP_KERNEL | __GFP_ZERO);
 	strscpy(src, "f0cacc1a0000000", KASAN_GRANULE_SIZE);
+	OPTIMIZER_HIDE_VAR(src);
 
 	/*
 	 * Make sure that strscpy() does not trigger KASAN if it overreads into

mm/kasan/shadow.c

···
 	pte_t pte;
 	int index;
 
-	if (likely(!pte_none(ptep_get(ptep))))
-		return 0;
+	arch_leave_lazy_mmu_mode();
 
 	index = PFN_DOWN(addr - data->start);
 	page = data->pages[index];
···
 		data->pages[index] = NULL;
 	}
 	spin_unlock(&init_mm.page_table_lock);
+
+	arch_enter_lazy_mmu_mode();
 
 	return 0;
 }
···
 static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr,
 					void *unused)
 {
-	unsigned long page;
+	pte_t pte;
+	int none;
 
-	page = (unsigned long)__va(pte_pfn(ptep_get(ptep)) << PAGE_SHIFT);
+	arch_leave_lazy_mmu_mode();
 
 	spin_lock(&init_mm.page_table_lock);
-
-	if (likely(!pte_none(ptep_get(ptep)))) {
+	pte = ptep_get(ptep);
+	none = pte_none(pte);
+	if (likely(!none))
 		pte_clear(&init_mm, addr, ptep);
-		free_page(page);
-	}
 	spin_unlock(&init_mm.page_table_lock);
+
+	if (likely(!none))
+		__free_page(pfn_to_page(pte_pfn(pte)));
+
+	arch_enter_lazy_mmu_mode();
 
 	return 0;
 }

mm/kmemleak.c

···
 		else if (untagged_objp == untagged_ptr || alias)
 			return object;
 		else {
+			/*
+			 * Printk deferring due to the kmemleak_lock held.
+			 * This is done to avoid deadlock.
+			 */
+			printk_deferred_enter();
 			kmemleak_warn("Found object by alias at 0x%08lx\n",
 				      ptr);
 			dump_object_info(object);
+			printk_deferred_exit();
 			break;
 		}
 	}
···
 		else if (untagged_objp + parent->size <= untagged_ptr)
 			link = &parent->rb_node.rb_right;
 		else {
+			/*
+			 * Printk deferring due to the kmemleak_lock held.
+			 * This is done to avoid deadlock.
+			 */
+			printk_deferred_enter();
 			kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
 				      ptr);
 			/*
···
 			 * be freed while the kmemleak_lock is held.
 			 */
 			dump_object_info(parent);
+			printk_deferred_exit();
 			return -EEXIST;
 		}
 	}
···
 
 	raw_spin_lock_irqsave(&kmemleak_lock, flags);
 	object = __find_and_remove_object(ptr, 1, objflags);
-	if (!object) {
-#ifdef DEBUG
-		kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
-			      ptr, size);
-#endif
+	if (!object)
 		goto unlock;
-	}
 
 	/*
 	 * Create one or two objects that may result from the memory block
···
 
 unlock:
 	raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
-	if (object)
+	if (object) {
 		__delete_object(object);
+	} else {
+#ifdef DEBUG
+		kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
+			      ptr, size);
+#endif
+	}
 
 out:
 	if (object_l)

mm/percpu.c

···
 #endif /* BUILD_EMBED_FIRST_CHUNK */
 
 #ifdef BUILD_PAGE_FIRST_CHUNK
-#include <asm/pgalloc.h>
+#include <linux/pgalloc.h>
 
 #ifndef P4D_TABLE_SIZE
 #define P4D_TABLE_SIZE PAGE_SIZE
···
 
 	if (pgd_none(*pgd)) {
 		p4d = memblock_alloc_or_panic(P4D_TABLE_SIZE, P4D_TABLE_SIZE);
-		pgd_populate(&init_mm, pgd, p4d);
+		pgd_populate_kernel(addr, pgd, p4d);
 	}
 
 	p4d = p4d_offset(pgd, addr);
 	if (p4d_none(*p4d)) {
 		pud = memblock_alloc_or_panic(PUD_TABLE_SIZE, PUD_TABLE_SIZE);
-		p4d_populate(&init_mm, p4d, pud);
+		p4d_populate_kernel(addr, p4d, pud);
 	}
 
 	pud = pud_offset(p4d, addr);

mm/sparse-vmemmap.c

···
 #include <linux/spinlock.h>
 #include <linux/vmalloc.h>
 #include <linux/sched.h>
+#include <linux/pgalloc.h>
 
 #include <asm/dma.h>
-#include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
 
 #include "hugetlb_vmemmap.h"
···
 		if (!p)
 			return NULL;
 		pud_init(p);
-		p4d_populate(&init_mm, p4d, p);
+		p4d_populate_kernel(addr, p4d, p);
 	}
 	return p4d;
 }
···
 		void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
 		if (!p)
 			return NULL;
-		pgd_populate(&init_mm, pgd, p);
+		pgd_populate_kernel(addr, pgd, p);
 	}
 	return pgd;
 }
···
 
 	if (r < 0)
 		return NULL;
-
-	if (system_state == SYSTEM_BOOTING)
-		memmap_boot_pages_add(DIV_ROUND_UP(end - start, PAGE_SIZE));
-	else
-		memmap_pages_add(DIV_ROUND_UP(end - start, PAGE_SIZE));
 
 	return pfn_to_page(pfn);
 }

mm/sparse.c

···
 	 */
 	sparsemap_buf = memmap_alloc(size, section_map_size(), addr, nid, true);
 	sparsemap_buf_end = sparsemap_buf + size;
-#ifndef CONFIG_SPARSEMEM_VMEMMAP
-	memmap_boot_pages_add(DIV_ROUND_UP(size, PAGE_SIZE));
-#endif
 }
 
 static void __init sparse_buffer_fini(void)
···
 				sparse_buffer_fini();
 				goto failed;
 			}
+			memmap_boot_pages_add(DIV_ROUND_UP(PAGES_PER_SECTION * sizeof(struct page),
+							   PAGE_SIZE));
 			sparse_init_early_section(nid, map, pnum, 0);
 		}
 	}
···
 	unsigned long start = (unsigned long) pfn_to_page(pfn);
 	unsigned long end = start + nr_pages * sizeof(struct page);
 
-	memmap_pages_add(-1L * (DIV_ROUND_UP(end - start, PAGE_SIZE)));
 	vmemmap_free(start, end, altmap);
 }
 static void free_map_bootmem(struct page *memmap)
···
 	 * The memmap of early sections is always fully populated. See
 	 * section_activate() and pfn_valid() .
 	 */
-	if (!section_is_early)
+	if (!section_is_early) {
+		memmap_pages_add(-1L * (DIV_ROUND_UP(nr_pages * sizeof(struct page), PAGE_SIZE)));
 		depopulate_section_memmap(pfn, nr_pages, altmap);
-	else if (memmap)
+	} else if (memmap) {
+		memmap_boot_pages_add(-1L * (DIV_ROUND_UP(nr_pages * sizeof(struct page),
+							  PAGE_SIZE)));
 		free_map_bootmem(memmap);
+	}
 
 	if (empty)
 		ms->section_mem_map = (unsigned long)NULL;
···
 		section_deactivate(pfn, nr_pages, altmap);
 		return ERR_PTR(-ENOMEM);
 	}
+	memmap_pages_add(DIV_ROUND_UP(nr_pages * sizeof(struct page), PAGE_SIZE));
 
 	return memmap;
 }

mm/userfaultfd.c

···
 		folio_unlock(src_folio);
 		folio_put(src_folio);
 	}
-	if (dst_pte)
-		pte_unmap(dst_pte);
+	/*
+	 * Unmap in reverse order (LIFO) to maintain proper kmap_local
+	 * index ordering when CONFIG_HIGHPTE is enabled. We mapped dst_pte
+	 * first, then src_pte, so we must unmap src_pte first, then dst_pte.
+	 */
 	if (src_pte)
 		pte_unmap(src_pte);
+	if (dst_pte)
+		pte_unmap(dst_pte);
 	mmu_notifier_invalidate_range_end(&range);
 	if (si)
 		put_swap_device(si);

rust/kernel/mm/virt.rs

···
 ///
 /// For the duration of 'a, the referenced vma must be undergoing initialization in an
 /// `f_ops->mmap()` hook.
+#[repr(transparent)]
 pub struct VmaNew {
     vma: VmaRef,
 }

scripts/Makefile.kasan

···
 		hwasan-use-short-granules=0 \
 		hwasan-inline-all-checks=0
 
-# Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
-ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
-	kasan_params += hwasan-kernel-mem-intrinsic-prefix=1
-endif
+# Instrument memcpy/memset/memmove calls by using instrumented __(hw)asan_mem*().
+ifdef CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX
+	ifdef CONFIG_CC_IS_GCC
+		kasan_params += asan-kernel-mem-intrinsic-prefix=1
+	else
+		kasan_params += hwasan-kernel-mem-intrinsic-prefix=1
+	endif
+endif # CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX
 
 endif # CONFIG_KASAN_SW_TAGS
 

tools/testing/selftests/mm/cow.c

···
 	}
 
 	/* Read from the page to populate the shared zeropage. */
-	FORCE_READ(mem);
-	FORCE_READ(smem);
+	FORCE_READ(*mem);
+	FORCE_READ(*smem);
 
 	fn(mem, smem, pagesize);
 munmap:

tools/testing/selftests/mm/guard-regions.c

···
 		if (write)
 			*ptr = 'x';
 		else
-			FORCE_READ(ptr);
+			FORCE_READ(*ptr);
 	}
 
 	signal_jump_set = false;

tools/testing/selftests/mm/hugetlb-madvise.c

···
 	unsigned long i;
 
 	for (i = 0; i < nr_pages; i++) {
+		unsigned long *addr2 =
+			((unsigned long *)(addr + (i * huge_page_size)));
 		/* Prevent the compiler from optimizing out the entire loop: */
-		FORCE_READ(((unsigned long *)(addr + (i * huge_page_size))));
+		FORCE_READ(*addr2);
 	}
 }
 

tools/testing/selftests/mm/migration.c

···
 		 * the memory access actually happens and prevents the compiler
 		 * from optimizing away this entire loop.
 		 */
-		FORCE_READ((uint64_t *)ptr);
+		FORCE_READ(*(uint64_t *)ptr);
 	}
 
 	return NULL;

tools/testing/selftests/mm/pagemap_ioctl.c

···
 
 	ret = madvise(mem, hpage_size, MADV_HUGEPAGE);
 	if (!ret) {
-		FORCE_READ(mem);
+		FORCE_READ(*mem);
 
 		ret = pagemap_ioctl(mem, hpage_size, &vec, 1, 0,
 				    0, PAGE_IS_PFNZERO, 0, 0, PAGE_IS_PFNZERO);

tools/testing/selftests/mm/split_huge_page_test.c

···
 	}
 	madvise(*addr, fd_size, MADV_HUGEPAGE);
 
-	for (size_t i = 0; i < fd_size; i++)
-		FORCE_READ((*addr + i));
+	for (size_t i = 0; i < fd_size; i++) {
+		char *addr2 = *addr + i;
+
+		FORCE_READ(*addr2);
+	}
 
 	if (!check_huge_file(*addr, fd_size / pmd_pagesize, pmd_pagesize)) {
 		ksft_print_msg("No large pagecache folio generated, please provide a filesystem supporting large folio\n");

tools/testing/selftests/mm/vm_util.h

···
  * anything with it in order to trigger a read page fault. We therefore must use
  * volatile to stop the compiler from optimising this away.
  */
-#define FORCE_READ(x) (*(volatile typeof(x) *)x)
+#define FORCE_READ(x) (*(const volatile typeof(x) *)&(x))
 
 extern unsigned int __page_size;
 extern unsigned int __page_shift;