+ mm-hugetlb_vmemmap-add-missing-smp_wmb-before-set_pte_at.patch added to mm-unstable branch

+ mm-hugetlb_vmemmap-add-missing-smp_wmb-before-set_pte_at.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm: hugetlb_vmemmap: add missing smp_wmb() before set_pte_at()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-hugetlb_vmemmap-add-missing-smp_wmb-before-set_pte_at.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb_vmemmap-add-missing-smp_wmb-before-set_pte_at.patch

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

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------------------------------------------------------
From: Miaohe Lin <linmiaohe@huawei.com>
Subject: mm: hugetlb_vmemmap: add missing smp_wmb() before set_pte_at()
Date: Tue, 16 Aug 2022 21:05:51 +0800

The memory barrier smp_wmb() is needed to make sure that preceding stores
to the page contents become visible before the below set_pte_at() write.

Link: https://lkml.kernel.org/r/20220816130553.31406-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb_vmemmap.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/mm/hugetlb_vmemmap.c~mm-hugetlb_vmemmap-add-missing-smp_wmb-before-set_pte_at
+++ a/mm/hugetlb_vmemmap.c
@@ -287,6 +287,11 @@ static void vmemmap_restore_pte(pte_t *p
 	copy_page(to, (void *)walk->reuse_addr);
 	reset_struct_pages(to);
 
+	/*
+	 * Makes sure that preceding stores to the page contents become visible
+	 * before the set_pte_at() write.
+	 */
+	smp_wmb();
 	set_pte_at(&init_mm, addr, pte, mk_pte(page, pgprot));
 }
 
_

Patches currently in -mm which might be from linmiaohe@huawei.com are

mm-hugetlb-avoid-corrupting-page-mapping-in-hugetlb_mcopy_atomic_pte.patch
mm-page_alloc-minor-clean-up-for-memmap_init_compound.patch
hugetlb_cgroup-remove-unneeded-nr_pages-0-check.patch
hugetlb_cgroup-hugetlbfs-use-helper-macro-sz_1kmg.patch
hugetlb_cgroup-remove-unneeded-return-value.patch
hugetlb_cgroup-use-helper-macro-numa_no_node.patch
hugetlb_cgroup-use-helper-for_each_hstate-and-hstate_index.patch
mm-hugetlb-fix-incorrect-update-of-max_huge_pages.patch
mm-hugetlb-fix-warn_onkobj-in-sysfs_create_group.patch
mm-hugetlb-fix-missing-call-to-restore_reserve_on_error.patch
mm-hugetlb_vmemmap-add-missing-smp_wmb-before-set_pte_at.patch
mm-hugetlb-fix-sysfs-group-leak-in-hugetlb_unregister_node.patch
mm-hugetlb-make-detecting-shared-pte-more-reliable.patch