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Date: Tue, 10 Oct 2017 21:50:25 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org,
Alexandru Moise <00moses.alexander00@...il.com>,
Anshuman Khandual <khandual@...ux.vnet.ibm.com>,
Michal Hocko <mhocko@...e.com>,
Andrea Arcangeli <aarcange@...hat.com>,
Minchan Kim <minchan@...nel.org>,
Hillf Danton <hdanton@...a.com>, Shaohua Li <shli@...com>,
Mike Rapoport <rppt@...ux.vnet.ibm.com>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Mel Gorman <mgorman@...hsingularity.net>,
David Rientjes <rientjes@...gle.com>,
Rik van Riel <riel@...hat.com>,
Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 4.13 097/160] mm, hugetlb, soft_offline: save compound page order before page migration
4.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Alexandru Moise <00moses.alexander00@...il.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.GA12053@gmail.com
Fixes: c3114a84f7f9 ("mm: hugetlb: soft-offline: dissolve source hugepage after successful migration")
Signed-off-by: Alexandru Moise <00moses.alexander00@...il.com>
Cc: Anshuman Khandual <khandual@...ux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@...e.com>
Cc: Andrea Arcangeli <aarcange@...hat.com>
Cc: Minchan Kim <minchan@...nel.org>
Cc: Hillf Danton <hdanton@...a.com>
Cc: Shaohua Li <shli@...com>
Cc: Mike Rapoport <rppt@...ux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Mel Gorman <mgorman@...hsingularity.net>
Cc: David Rientjes <rientjes@...gle.com>
Cc: Rik van Riel <riel@...hat.com>
Cc: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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;
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