The patch titled
Subject: mm/memory-failure: unlock_page before put_page
has been added to the -mm tree. Its filename is
mm-memory-failure-unlock_page-before-put_page.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memory-failure-unlock_page-before-put_page.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memory-failure-unlock_page-before-put_page.patch
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------------------------------------------------------
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Subject: mm/memory-failure: unlock_page before put_page
Recently I addressed a few of hwpoison race problems and the patches are
merged on v4.2-rc1. It made progress, but unfortunately some problems
still remain due to less coverage of my testing. So I'm trying to fix or
avoid them in this series.
One point I'm expecting to discuss is that patch 4/5 changes the page flag
set to be checked on free time. In current behavior, __PG_HWPOISON is not
supposed to be set when the page is freed. I think that there is no
strong reason for this behavior, and it causes a problem hard to fix only
in error handler side (because __PG_HWPOISON could be set at arbitrary
timing.) So I suggest to change it.
With this patchset, hwpoison stress testing in official mce-test testsuite
(which previously failed) passes.
This patch (of 5):
In "just unpoisoned" path, we do put_page and then unlock_page, which is a
wrong order and causes "freeing locked page" bug. So let's fix it.
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>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN mm/memory-failure.c~mm-memory-failure-unlock_page-before-put_page mm/memory-failure.c
--- a/mm/memory-failure.c~mm-memory-failure-unlock_page-before-put_page
+++ a/mm/memory-failure.c
@@ -1209,9 +1209,9 @@ int memory_failure(unsigned long pfn, in
if (!PageHWPoison(p)) {
printk(KERN_ERR "MCE %#lx: just unpoisoned\n", pfn);
atomic_long_sub(nr_pages, &num_poisoned_pages);
+ unlock_page(hpage);
put_page(hpage);
- res = 0;
- goto out;
+ return 0;
}
if (hwpoison_filter(p)) {
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-check-__pg_hwpoison-separately-from-page_flags_check_at_.patch
mm-memory-failure-set-pagehwpoison-before-migrate_pages.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
hugetlbfs-add-hugetlbfs_fallocate-fix.patch
mm-madvise-allow-remove-operation-for-hugetlbfs.patch
mempolicy-get-rid-of-duplicated-check-for-vmavm_pfnmap-in-queue_pages_range.patch
mm-page_isolation-make-set-unset_migratetype_isolate-file-local.patch
mm-compaction-more-robust-check-for-scanners-meeting.patch
mm-compaction-simplify-handling-restart-position-in-free-pages-scanner.patch
mm-compaction-encapsulate-resetting-cached-scanner-positions.patch
mm-compaction-skip-compound-pages-by-order-in-free-scanner.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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