Commit 56f2fb14 authored Dec 12, 2012 by Naoya Horiguchi Committed by Linus Torvalds Dec 12, 2012

mm/hugetlb.c: fix warning on freeing hwpoisoned hugepage



Fix the warning from __list_del_entry() which is triggered when a process
tries to do free_huge_page() for a hwpoisoned hugepage.

free_huge_page() can be called for hwpoisoned hugepage from
unpoison_memory().  This function gets refcount once and clears
PageHWPoison, and then puts refcount twice to return the hugepage back to
free pool.  The second put_page() finally reaches free_huge_page().

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 5f24ae58

mm/hugetlb.c

+7 −1

Original line number	Original line	Diff line number	Diff line
	@@ -3172,7 +3172,13 @@ int dequeue_hwpoisoned_huge_page(struct page *hpage)

	spin_lock(&hugetlb_lock);		spin_lock(&hugetlb_lock);
	if (is_hugepage_on_freelist(hpage)) {		if (is_hugepage_on_freelist(hpage)) {
	list_del(&hpage->lru);		/*
			* Hwpoisoned hugepage isn't linked to activelist or freelist,
			* but dangling hpage->lru can trigger list-debug warnings
			* (this happens when we call unpoison_memory() on it),
			* so let it point to itself with list_del_init().
			*/
			list_del_init(&hpage->lru);
	set_page_refcounted(hpage);		set_page_refcounted(hpage);
	h->free_huge_pages--;		h->free_huge_pages--;
	h->free_huge_pages_node[nid]--;		h->free_huge_pages_node[nid]--;