+ hugetlb-freeze-allocated-pages-before-creating-hugetlb-pages-v3.patch added to mm-unstable branch

+ hugetlb-freeze-allocated-pages-before-creating-hugetlb-pages-v3.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: hugetlb-freeze-allocated-pages-before-creating-hugetlb-pages-v3
has been added to the -mm mm-unstable branch.  Its filename is
     hugetlb-freeze-allocated-pages-before-creating-hugetlb-pages-v3.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/hugetlb-freeze-allocated-pages-before-creating-hugetlb-pages-v3.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: Mike Kravetz <mike.kravetz@oracle.com>
Subject: hugetlb-freeze-allocated-pages-before-creating-hugetlb-pages-v3
Date: Wed, 21 Sep 2022 13:27:02 -0700

fix NULL pointer dereference in alloc_buddy_huge_page caused by not
checking for page before attempting to freeze.  Thanks Naoya.

Link: https://lkml.kernel.org/r/20220921202702.106069-1-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---


--- a/mm/hugetlb.c~hugetlb-freeze-allocated-pages-before-creating-hugetlb-pages-v3
+++ a/mm/hugetlb.c
@@ -1957,7 +1957,7 @@ retry:
 	page = __alloc_pages(gfp_mask, order, nid, nmask);
 
 	/* Freeze head page */
-	if (!page_ref_freeze(page, 1)) {
+	if (page && !page_ref_freeze(page, 1)) {
 		__free_pages(page, order);
 		if (retry) {	/* retry once */
 			retry = false;
_

Patches currently in -mm which might be from mike.kravetz@oracle.com are

hugetlbfs-revert-use-i_mmap_rwsem-to-address-page-fault-truncate-race.patch
hugetlbfs-revert-use-i_mmap_rwsem-for-more-pmd-sharing-synchronization.patch
hugetlb-rename-remove_huge_page-to-hugetlb_delete_from_page_cache.patch
hugetlb-create-remove_inode_single_folio-to-remove-single-file-folio.patch
hugetlb-rename-vma_shareable-and-refactor-code.patch
hugetlb-add-vma-based-lock-for-pmd-sharing.patch
hugetlb-add-vma-based-lock-for-pmd-sharing-fix.patch
hugetlb-create-hugetlb_unmap_file_folio-to-unmap-single-file-folio.patch
hugetlb-use-new-vma_lock-for-pmd-sharing-synchronization.patch
hugetlb-clean-up-code-checking-for-fault-truncation-races.patch
hugetlb-clean-up-code-checking-for-fault-truncation-races-fix.patch
hugetlb-freeze-allocated-pages-before-creating-hugetlb-pages.patch
hugetlb-freeze-allocated-pages-before-creating-hugetlb-pages-v3.patch
hugetlb-simplify-hugetlb-handling-in-follow_page_mask.patch