From: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Subject: 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@xxxxxxxxxx Fixes: 78bb920344b8 ("mm: hwpoison: dissolve in-use hugepage in unrecoverable memory error") Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Aneesh Kumar <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Cc: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/hugetlbfs/inode.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff -puN fs/hugetlbfs/inode.c~mm-hugetlbfs-fix-hwpoison-reserve-accounting fs/hugetlbfs/inode.c --- a/fs/hugetlbfs/inode.c~mm-hugetlbfs-fix-hwpoison-reserve-accounting +++ a/fs/hugetlbfs/inode.c @@ -842,9 +842,12 @@ static int hugetlbfs_error_remove_page(s 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; } _