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authorXishi Qiu <qiuxishi@huawei.com>2014-02-14 10:33:35 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-20 11:06:12 -0800
commit6843d9254c8cd2decb30edaf7deffaad4d244c51 (patch)
treedffc1779a7aef3aeb8128d2daa0ec5cd40527e32
parent2d9258e499abbbe55fb60a26995e378f2b51d513 (diff)
mm: fix process accidentally killed by mce because of huge page migration
Based on c8721bbbdd36382de51cd6b7a56322e0acca2414 upstream, but only the bugfix portion pulled out. Hi Naoya or Greg, We found a bug in 3.10.x. The problem is that we accidentally have a hwpoisoned hugepage in free hugepage list. It could happend in the the following scenario: process A process B migrate_huge_page put_page (old hugepage) linked to free hugepage list hugetlb_fault hugetlb_no_page alloc_huge_page dequeue_huge_page_vma dequeue_huge_page_node (steal hwpoisoned hugepage) set_page_hwpoison_huge_page dequeue_hwpoisoned_huge_page (fail to dequeue) I tested this bug, one process keeps allocating huge page, and I use sysfs interface to soft offline a huge page, then received: "MCE: Killing UCP:2717 due to hardware memory corruption fault at 8200034" Upstream kernel is free from this bug because of these two commits: f15bdfa802bfa5eb6b4b5a241b97ec9fa1204a35 mm/memory-failure.c: fix memory leak in successful soft offlining c8721bbbdd36382de51cd6b7a56322e0acca2414 mm: memory-hotplug: enable memory hotplug to handle hugepage The first one, although the problem is about memory leak, this patch moves unset_migratetype_isolate(), which is important to avoid the race. The latter is not a bug fix and it's too big, so I rewrite a small one. The following patch can fix this bug.(please apply f15bdfa802bf first) Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--mm/hugetlb.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 40ad2c6e0ca9..aa3b9a63394b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -21,6 +21,7 @@
#include <linux/rmap.h>
#include <linux/swap.h>
#include <linux/swapops.h>
+#include <linux/page-isolation.h>
#include <asm/page.h>
#include <asm/pgtable.h>
@@ -517,9 +518,15 @@ static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
{
struct page *page;
- if (list_empty(&h->hugepage_freelists[nid]))
+ list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
+ if (!is_migrate_isolate_page(page))
+ break;
+ /*
+ * if 'non-isolated free hugepage' not found on the list,
+ * the allocation fails.
+ */
+ if (&h->hugepage_freelists[nid] == &page->lru)
return NULL;
- page = list_entry(h->hugepage_freelists[nid].next, struct page, lru);
list_move(&page->lru, &h->hugepage_activelist);
set_page_refcounted(page);
h->free_huge_pages--;