From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753840AbcBOAPL (ORCPT ); Sun, 14 Feb 2016 19:15:11 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:41029 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753248AbcBNWeR (ORCPT ); Sun, 14 Feb 2016 17:34:17 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Naoya Horiguchi , David Rientjes , Dave Hansen , Mel Gorman , Joonsoo Kim , Hillf Danton , Mike Kravetz , Andrew Morton , Linus Torvalds Subject: [PATCH 4.3 027/200] mm: hugetlb: fix hugepage memory leak caused by wrong reserve count Date: Sun, 14 Feb 2016 14:20:34 -0800 Message-Id: <20160214222218.110639388@linuxfoundation.org> X-Mailer: git-send-email 2.7.1 In-Reply-To: <20160214222217.084543173@linuxfoundation.org> References: <20160214222217.084543173@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Naoya Horiguchi commit a88c769548047b21f76fd71e04b6a3300ff17160 upstream. When dequeue_huge_page_vma() in alloc_huge_page() fails, we fall back on alloc_buddy_huge_page() to directly create a hugepage from the buddy allocator. In that case, however, if alloc_buddy_huge_page() succeeds we don't decrement h->resv_huge_pages, which means that successful hugetlb_fault() returns without releasing the reserve count. As a result, subsequent hugetlb_fault() might fail despite that there are still free hugepages. This patch simply adds decrementing code on that code path. I reproduced this problem when testing v4.3 kernel in the following situation: - the test machine/VM is a NUMA system, - hugepage overcommiting is enabled, - most of hugepages are allocated and there's only one free hugepage which is on node 0 (for example), - another program, which calls set_mempolicy(MPOL_BIND) to bind itself to node 1, tries to allocate a hugepage, - the allocation should fail but the reserve count is still hold. Signed-off-by: Naoya Horiguchi Cc: David Rientjes Cc: Dave Hansen Cc: Mel Gorman Cc: Joonsoo Kim Cc: Hillf Danton Cc: Mike Kravetz Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/hugetlb.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1790,7 +1790,10 @@ struct page *alloc_huge_page(struct vm_a page = alloc_buddy_huge_page(h, NUMA_NO_NODE); if (!page) goto out_uncharge_cgroup; - + if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) { + SetPagePrivate(page); + h->resv_huge_pages--; + } spin_lock(&hugetlb_lock); list_move(&page->lru, &h->hugepage_activelist); /* Fall through */