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 7a24f91af29e43c53a3bc2b394ec97a81b4eaab7..3a2fea8d211d7de47b97657e74ce577d2e0ba680 100644 (file)
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -654,9 +654,10 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 
                mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 
+               set_page_huge_active(page);
                /*
                 * unlock_page because locked by add_to_page_cache()
-                * page_put due to reference from alloc_huge_page()
+                * put_page() due to reference from alloc_huge_page()
                 */
                unlock_page(page);
                put_page(page);

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index d34112fb3d52640d0ce7465f1927f2765810a7f7..cae7fd680448842b45d54c1251fe3e5c0a997677 100644 (file)
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -541,6 +541,9 @@ static inline void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr
        set_huge_pte_at(mm, addr, ptep, pte);
 }
 #endif
+
+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 0b60ab3966968a8bc082decea240cfa925306b2a..532ba5e3a90b1ee124a63dd97ae2b8a08232040b 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1201,7 +1201,7 @@ 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]);