+ mmhwpoison-take-free-pages-off-the-buddy-freelists-for-hugetlb.patch added to -mm tree

+ mmhwpoison-take-free-pages-off-the-buddy-freelists-for-hugetlb.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm,hwpoison: take free pages off the buddy freelists for hugetlb
has been added to the -mm tree.  Its filename is
     mmhwpoison-take-free-pages-off-the-buddy-freelists-for-hugetlb.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mmhwpoison-take-free-pages-off-the-buddy-freelists-for-hugetlb.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mmhwpoison-take-free-pages-off-the-buddy-freelists-for-hugetlb.patch

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------------------------------------------------------
From: Oscar Salvador <osalvador@suse.de>
Subject: mm,hwpoison: take free pages off the buddy freelists for hugetlb

Currently, free hugetlb get dissolved, but we also need to make sure to
take the poisoned subpage off the buddy frelists, so no one stumbles upon
it (see previous patch for more information).

Link: https://lkml.kernel.org/r/20201013144447.6706-4-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory-failure.c |   19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

--- a/mm/memory-failure.c~mmhwpoison-take-free-pages-off-the-buddy-freelists-for-hugetlb
+++ a/mm/memory-failure.c
@@ -809,7 +809,7 @@ static int me_swapcache_clean(struct pag
  */
 static int me_huge_page(struct page *p, unsigned long pfn)
 {
-	int res = 0;
+	int res;
 	struct page *hpage = compound_head(p);
 	struct address_space *mapping;
 
@@ -820,6 +820,7 @@ static int me_huge_page(struct page *p,
 	if (mapping) {
 		res = truncate_error_page(hpage, pfn, mapping);
 	} else {
+		res = MF_FAILED;
 		unlock_page(hpage);
 		/*
 		 * migration entry prevents later access on error anonymous
@@ -828,8 +829,10 @@ static int me_huge_page(struct page *p,
 		 */
 		if (PageAnon(hpage))
 			put_page(hpage);
-		dissolve_free_huge_page(p);
-		res = MF_RECOVERED;
+		if (!dissolve_free_huge_page(p) && take_page_off_buddy(p)) {
+			page_ref_inc(p);
+			res = MF_RECOVERED;
+		}
 		lock_page(hpage);
 	}
 
@@ -1196,9 +1199,13 @@ static int memory_failure_hugetlb(unsign
 			}
 		}
 		unlock_page(head);
-		dissolve_free_huge_page(p);
-		action_result(pfn, MF_MSG_FREE_HUGE, MF_DELAYED);
-		return 0;
+		res = MF_FAILED;
+		if (!dissolve_free_huge_page(p) && take_page_off_buddy(p)) {
+			page_ref_inc(p);
+			res = MF_RECOVERED;
+		}
+		action_result(pfn, MF_MSG_FREE_HUGE, res);
+		return res == MF_RECOVERED ? 0 : -EBUSY;
 	}
 
 	lock_page(head);
_

Patches currently in -mm which might be from osalvador@suse.de are

mmhwpoison-drain-pcplists-before-bailing-out-for-non-buddy-zero-refcount-page.patch
mmhwpoison-take-free-pages-off-the-buddy-freelists.patch
mmhwpoison-take-free-pages-off-the-buddy-freelists-for-hugetlb.patch
mmhwpoison-drop-unneeded-pcplist-draining.patch