The patch titled
Subject: mm/memory-failure: give up error handling for non-tail-refcounted thp
has been added to the -mm tree. Its filename is
mm-memory-failure-give-up-error-handling-for-non-tail-refcounted-thp.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memory-failure-give-up-error-handling-for-non-tail-refcounted-thp.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memory-failure-give-up-error-handling-for-non-tail-refcounted-thp.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Subject: mm/memory-failure: give up error handling for non-tail-refcounted thp
"non anonymous thp" case is still racy with freeing thp, which causes
panic due to put_page() for refcount-0 page. It seems that closing up
this race might be hard (and/or not worth doing,) so let's give up the
error handling for this case.
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Dean Nelson <dnelson@xxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff -puN mm/memory-failure.c~mm-memory-failure-give-up-error-handling-for-non-tail-refcounted-thp mm/memory-failure.c
--- a/mm/memory-failure.c~mm-memory-failure-give-up-error-handling-for-non-tail-refcounted-thp
+++ a/mm/memory-failure.c
@@ -909,6 +909,15 @@ int get_hwpoison_page(struct page *page)
* directly for tail pages.
*/
if (PageTransHuge(head)) {
+ /*
+ * Non anonymous thp exists only in allocation/free time. We
+ * can't handle such a case correctly, so let's give it up.
+ * This should be better than triggering BUG_ON when kernel
+ * tries to touch a "partially handled" page.
+ */
+ if (!PageAnon(head))
+ return 0;
+
if (get_page_unless_zero(head)) {
if (PageTail(page))
get_page(page);
@@ -1134,15 +1143,6 @@ int memory_failure(unsigned long pfn, in
}
if (!PageHuge(p) && PageTransHuge(hpage)) {
- if (!PageAnon(hpage)) {
- pr_err("MCE: %#lx: non anonymous thp\n", pfn);
- if (TestClearPageHWPoison(p))
- atomic_long_sub(nr_pages, &num_poisoned_pages);
- put_page(p);
- if (p != hpage)
- put_page(hpage);
- return -EBUSY;
- }
if (unlikely(split_huge_page(hpage))) {
pr_err("MCE: %#lx: thp split failed\n", pfn);
if (TestClearPageHWPoison(p))
_
Patches currently in -mm which might be from n-horiguchi@xxxxxxxxxxxxx are
mm-memory-failure-unlock_page-before-put_page.patch
mm-memory-failure-fix-race-in-counting-num_poisoned_pages.patch
mm-memory-failure-give-up-error-handling-for-non-tail-refcounted-thp.patch
mm-memory-failure-check-__pg_hwpoison-separately-from-page_flags_check_at_.patch
hugetlb-make-the-function-vma_shareable-bool.patch
pagemap-check-permissions-and-capabilities-at-open-time.patch
pagemap-switch-to-the-new-format-and-do-some-cleanup.patch
pagemap-rework-hugetlb-and-thp-report.patch
pagemap-hide-physical-addresses-from-non-privileged-users.patch
pagemap-add-mmap-exclusive-bit-for-marking-pages-mapped-only-here.patch
pagemap-update-documentation.patch
pagemap-update-documentation-fix.patch
mm-page_isolation-remove-bogus-tests-for-isolated-pages.patch
mm-rename-and-move-get-set_freepage_migratetype.patch
mm-hugetlb-add-cache-of-descriptors-to-resv_map-for-region_add.patch
mm-hugetlb-add-region_del-to-delete-a-specific-range-of-entries.patch
mm-hugetlb-expose-hugetlb-fault-mutex-for-use-by-fallocate.patch
hugetlbfs-hugetlb_vmtruncate_list-needs-to-take-a-range-to-delete.patch
hugetlbfs-truncate_hugepages-takes-a-range-of-pages.patch
mm-hugetlb-vma_has_reserves-needs-to-handle-fallocate-hole-punch.patch
mm-hugetlb-alloc_huge_page-handle-areas-hole-punched-by-fallocate.patch
hugetlbfs-new-huge_add_to_page_cache-helper-routine.patch
hugetlbfs-add-hugetlbfs_fallocate.patch
mm-madvise-allow-remove-operation-for-hugetlbfs.patch
mm-page_isolation-make-set-unset_migratetype_isolate-file-local.patch
page-flags-trivial-cleanup-for-pagetrans-helpers.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages.patch
page-flags-define-pg_locked-behavior-on-compound-pages.patch
page-flags-define-behavior-of-fs-io-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-lru-related-flags-on-compound-pages.patch
page-flags-define-behavior-slb-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-xen-related-flags-on-compound-pages.patch
page-flags-define-pg_reserved-behavior-on-compound-pages.patch
page-flags-define-pg_swapbacked-behavior-on-compound-pages.patch
page-flags-define-pg_swapcache-behavior-on-compound-pages.patch
page-flags-define-pg_mlocked-behavior-on-compound-pages.patch
page-flags-define-pg_uncached-behavior-on-compound-pages.patch
page-flags-define-pg_uptodate-behavior-on-compound-pages.patch
page-flags-look-on-head-page-if-the-flag-is-encoded-in-page-mapping.patch
mm-sanitize-page-mapping-for-tail-pages.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
--
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