From: Muchun Song <songmuchun@bytedance.com>
Date: Fri, 5 Feb 2021 02:32:03 +0000 (-0800)
Subject: mm: hugetlbfs: fix cannot migrate the fallocated HugeTLB page
X-Git-Tag: v4.4.257~8
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c00e7c90c7b0dc9cbb36cc3b675c00d14304c1dc;p=thirdparty%2Fkernel%2Fstable.git

mm: hugetlbfs: fix cannot migrate the fallocated HugeTLB page

commit 585fc0d2871c9318c949fbf45b1f081edd489e96 upstream.

If a new hugetlb page is allocated during fallocate it will not be
marked as active (set_page_huge_active) which will result in a later
isolate_huge_page failure when the page migration code would like to
move that page.  Such a failure would be unexpected and wrong.

Only export set_page_huge_active, just leave clear_page_huge_active as
static.  Because there are no external users.

Link: https://lkml.kernel.org/r/20210115124942.46403-3-songmuchun@bytedance.com
Fixes: 70c3547e36f5 (hugetlbfs: add hugetlbfs_fallocate())
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 937c6ee1786f9..b743aa5bce0d2 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -661,8 +661,9 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 
 		mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 
+		set_page_huge_active(page);
 		/*
-		 * page_put due to reference from alloc_huge_page()
+		 * put_page() due to reference from alloc_huge_page()
 		 * unlock_page because locked by add_to_page_cache()
 		 */
 		put_page(page);
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index cc185525a94ba..c4a4a39a458dc 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -506,6 +506,9 @@ static inline void hugetlb_count_sub(long l, struct mm_struct *mm)
 {
 	atomic_long_sub(l, &mm->hugetlb_usage);
 }
+
+void set_page_huge_active(struct page *page);
+
 #else	/* CONFIG_HUGETLB_PAGE */
 struct hstate {};
 #define alloc_huge_page(v, a, r) NULL
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 7a23792230854..492fe02e89db3 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1189,7 +1189,7 @@ bool page_huge_active(struct page *page)
 }
 
 /* never called for tail page */
-static void set_page_huge_active(struct page *page)
+void set_page_huge_active(struct page *page)
 {
 	VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
 	SetPagePrivate(&page[1]);