4.13-stable review patch. If anyone has any objections, please let me know.
------------------ From: Alexandru Moise <00moses.alexande...@gmail.com> commit 19bfbe22f59a207417b2679e7e83c180419c9ec5 upstream. This fixes a bug in madvise() where if you'd try to soft offline a hugepage via madvise(), while walking the address range you'd end up, using the wrong page offset due to attempting to get the compound order of a former but presently not compound page, due to dissolving the huge page (since commit c3114a84f7f9: "mm: hugetlb: soft-offline: dissolve source hugepage after successful migration"). As a result I ended up with all my free pages except one being offlined. Link: http://lkml.kernel.org/r/20170912204306.ga12...@gmail.com Fixes: c3114a84f7f9 ("mm: hugetlb: soft-offline: dissolve source hugepage after successful migration") Signed-off-by: Alexandru Moise <00moses.alexande...@gmail.com> Cc: Anshuman Khandual <khand...@linux.vnet.ibm.com> Cc: Michal Hocko <mho...@suse.com> Cc: Andrea Arcangeli <aarca...@redhat.com> Cc: Minchan Kim <minc...@kernel.org> Cc: Hillf Danton <hdan...@sina.com> Cc: Shaohua Li <s...@fb.com> Cc: Mike Rapoport <r...@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shute...@linux.intel.com> Cc: Mel Gorman <mgor...@techsingularity.net> Cc: David Rientjes <rient...@google.com> Cc: Rik van Riel <r...@redhat.com> Cc: Naoya Horiguchi <n-horigu...@ah.jp.nec.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- mm/madvise.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/mm/madvise.c +++ b/mm/madvise.c @@ -614,18 +614,26 @@ static int madvise_inject_error(int beha { struct page *page; struct zone *zone; + unsigned int order; if (!capable(CAP_SYS_ADMIN)) return -EPERM; - for (; start < end; start += PAGE_SIZE << - compound_order(compound_head(page))) { + + for (; start < end; start += PAGE_SIZE << order) { int ret; ret = get_user_pages_fast(start, 1, 0, &page); if (ret != 1) return ret; + /* + * When soft offlining hugepages, after migrating the page + * we dissolve it, therefore in the second loop "page" will + * no longer be a compound page, and order will be 0. + */ + order = compound_order(compound_head(page)); + if (PageHWPoison(page)) { put_page(page); continue;
