Commit 8ace22bc authored Dec 14, 2018 by Yongkai Wu Committed by Linus Torvalds Dec 14, 2018

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 <nic_w@163.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent f5a222dc

mm/hugetlb.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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);

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