From 8ace22bce84014957da37e6b8baa49ee81c03366 Mon Sep 17 00:00:00 2001 From: Yongkai Wu Date: Fri, 14 Dec 2018 14:17:10 -0800 Subject: [PATCH] hugetlbfs: call VM_BUG_ON_PAGE earlier in free_huge_page() A stack trace was triggered by VM_BUG_ON_PAGE(page_mapcount(page), page) in free_huge_page(). Unfortunately, the page->mapping field was set to NULL before this test. This made it more difficult to determine the root cause of the problem. Move the VM_BUG_ON_PAGE tests earlier in the function so that if they do trigger more information is present in the page struct. Link: http://lkml.kernel.org/r/1543491843-23438-1-git-send-email-nic_w@163.com Signed-off-by: Yongkai Wu Acked-by: Michal Hocko Acked-by: Mike Kravetz Reviewed-by: William Kucharski Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 705a3e9cc910..a80832487981 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1248,10 +1248,11 @@ void free_huge_page(struct page *page) (struct hugepage_subpool *)page_private(page); bool restore_reserve; - set_page_private(page, 0); - page->mapping = NULL; VM_BUG_ON_PAGE(page_count(page), page); VM_BUG_ON_PAGE(page_mapcount(page), page); + + set_page_private(page, 0); + page->mapping = NULL; restore_reserve = PagePrivate(page); ClearPagePrivate(page);