From ab615a5b879292e83653be60aa82113f7c6f462d Mon Sep 17 00:00:00 2001 From: Mike Kravetz Date: Thu, 2 Nov 2017 15:59:41 -0700 Subject: [PATCH] fs/hugetlbfs/inode.c: fix hwpoison reserve accounting Calling madvise(MADV_HWPOISON) on a hugetlbfs page will result in bad (negative) reserved huge page counts. This may not happen immediately, but may happen later when the underlying file is removed or filesystem unmounted. For example: AnonHugePages: 0 kB ShmemHugePages: 0 kB HugePages_Total: 1 HugePages_Free: 0 HugePages_Rsvd: 18446744073709551615 HugePages_Surp: 0 Hugepagesize: 2048 kB In routine hugetlbfs_error_remove_page(), hugetlb_fix_reserve_counts is called after remove_huge_page. hugetlb_fix_reserve_counts is designed to only be called/used only if a failure is returned from hugetlb_unreserve_pages. Therefore, call hugetlb_unreserve_pages as required and only call hugetlb_fix_reserve_counts in the unlikely event that hugetlb_unreserve_pages returns an error. Link: http://lkml.kernel.org/r/20171019230007.17043-2-mike.kravetz@oracle.com Fixes: 78bb920344b8 ("mm: hwpoison: dissolve in-use hugepage in unrecoverable memory error") Signed-off-by: Mike Kravetz Acked-by: Naoya Horiguchi Cc: Michal Hocko Cc: Aneesh Kumar Cc: Anshuman Khandual Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/hugetlbfs/inode.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 59073e9f01a4..ed113ea17aff 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -842,9 +842,12 @@ static int hugetlbfs_error_remove_page(struct address_space *mapping, struct page *page) { struct inode *inode = mapping->host; + pgoff_t index = page->index; remove_huge_page(page); - hugetlb_fix_reserve_counts(inode); + if (unlikely(hugetlb_unreserve_pages(inode, index, index + 1, 1))) + hugetlb_fix_reserve_counts(inode); + return 0; }