From 09789e5de18e4e442870b2d700831f5cb802eb05 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Tue, 5 May 2015 16:23:35 -0700 Subject: mm/memory-failure: call shake_page() when error hits thp tail page Currently memory_failure() calls shake_page() to sweep pages out from pcplists only when the victim page is 4kB LRU page or thp head page. But we should do this for a thp tail page too. Consider that a memory error hits a thp tail page whose head page is on a pcplist when memory_failure() runs. Then, the current kernel skips shake_pages() part, so hwpoison_user_mappings() returns without calling split_huge_page() nor try_to_unmap() because PageLRU of the thp head is still cleared due to the skip of shake_page(). As a result, me_huge_page() runs for the thp, which is broken behavior. One effect is a leak of the thp. And another is to fail to isolate the memory error, so later access to the error address causes another MCE, which kills the processes which used the thp. This patch fixes this problem by calling shake_page() for thp tail case. Fixes: 385de35722c9 ("thp: allow a hwpoisoned head page to be put back to LRU") Signed-off-by: Naoya Horiguchi Reviewed-by: Andi Kleen Acked-by: Dean Nelson Cc: Andrea Arcangeli Cc: Hidetoshi Seto Cc: Jin Dongming Cc: [3.4+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory-failure.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'mm/memory-failure.c') diff --git a/mm/memory-failure.c b/mm/memory-failure.c index d9359b770cd9..22e0f270e4f7 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1187,10 +1187,10 @@ int memory_failure(unsigned long pfn, int trapno, int flags) * The check (unnecessarily) ignores LRU pages being isolated and * walked by the page reclaim code, however that's not a big loss. */ - if (!PageHuge(p) && !PageTransTail(p)) { - if (!PageLRU(p)) - shake_page(p, 0); - if (!PageLRU(p)) { + if (!PageHuge(p)) { + if (!PageLRU(hpage)) + shake_page(hpage, 0); + if (!PageLRU(hpage)) { /* * shake_page could have turned it free. */ -- cgit v1.2.3 From 602498f9aa43d4951eece3fd6ad95a6d0a78d537 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Tue, 5 May 2015 16:23:46 -0700 Subject: mm: soft-offline: fix num_poisoned_pages counting on concurrent events If multiple soft offline events hit one free page/hugepage concurrently, soft_offline_page() can handle the free page/hugepage multiple times, which makes num_poisoned_pages counter increased more than once. This patch fixes this wrong counting by checking TestSetPageHWPoison for normal papes and by checking the return value of dequeue_hwpoisoned_huge_page() for hugepages. Signed-off-by: Naoya Horiguchi Acked-by: Dean Nelson Cc: Andi Kleen Cc: [3.14+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory-failure.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'mm/memory-failure.c') diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 22e0f270e4f7..501820c815b3 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1777,12 +1777,12 @@ int soft_offline_page(struct page *page, int flags) } else if (ret == 0) { /* for free pages */ if (PageHuge(page)) { set_page_hwpoison_huge_page(hpage); - dequeue_hwpoisoned_huge_page(hpage); - atomic_long_add(1 << compound_order(hpage), + if (!dequeue_hwpoisoned_huge_page(hpage)) + atomic_long_add(1 << compound_order(hpage), &num_poisoned_pages); } else { - SetPageHWPoison(page); - atomic_long_inc(&num_poisoned_pages); + if (!TestSetPageHWPoison(page)) + atomic_long_inc(&num_poisoned_pages); } } unset_migratetype_isolate(page, MIGRATE_MOVABLE); -- cgit v1.2.3