HWPOISON, hugetlb: add free check to dequeue_hwpoison_huge_page()
This check is necessary to avoid race between dequeue and allocation,
which can cause a free hugepage to be dequeued twice and get kernel unstable.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0fa9de8..deb7beb 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2955,18 +2955,39 @@
hugetlb_acct_memory(h, -(chg - freed));
}
+/* Should be called in hugetlb_lock */
+static int is_hugepage_on_freelist(struct page *hpage)
+{
+ struct page *page;
+ struct page *tmp;
+ struct hstate *h = page_hstate(hpage);
+ int nid = page_to_nid(hpage);
+
+ list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
+ if (page == hpage)
+ return 1;
+ return 0;
+}
+
+#ifdef CONFIG_MEMORY_FAILURE
/*
* This function is called from memory failure code.
* Assume the caller holds page lock of the head page.
*/
-void __isolate_hwpoisoned_huge_page(struct page *hpage)
+int dequeue_hwpoisoned_huge_page(struct page *hpage)
{
struct hstate *h = page_hstate(hpage);
int nid = page_to_nid(hpage);
+ int ret = -EBUSY;
spin_lock(&hugetlb_lock);
- list_del(&hpage->lru);
- h->free_huge_pages--;
- h->free_huge_pages_node[nid]--;
+ if (is_hugepage_on_freelist(hpage)) {
+ list_del(&hpage->lru);
+ h->free_huge_pages--;
+ h->free_huge_pages_node[nid]--;
+ ret = 0;
+ }
spin_unlock(&hugetlb_lock);
+ return ret;
}
+#endif