mm: hugetlb: fix missing put_page in gather_surplus_pages()

The VM_BUG_ON_PAGE avoids the generation of any code, even if that
expression has side-effects when !CONFIG_DEBUG_VM.

Link: https://lkml.kernel.org/r/20210126031009.96266-1-songmuchun@bytedance.com
Fixes: e5dfacebe4a4 ("mm/hugetlb.c: just use put_page_testzero() instead of page_count()")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d78111f0fa2cbf3936582eb9f7189fcda08e14e5..4bdb58ab14cbbd659a1f9ca2e531a995fed03077 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2047,13 +2047,16 @@ retry:
 
        /* Free the needed pages to the hugetlb pool */
        list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
+               int zeroed;
+
                if ((--needed) < 0)
                        break;
                /*
                 * This page is now managed by the hugetlb allocator and has
                 * no users -- drop the buddy allocator's reference.
                 */
-               VM_BUG_ON_PAGE(!put_page_testzero(page), page);
+               zeroed = put_page_testzero(page);
+               VM_BUG_ON_PAGE(!zeroed, page);
                enqueue_huge_page(h, page);
        }
 free: