From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934773AbaFIW6K (ORCPT ); Mon, 9 Jun 2014 18:58:10 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:57062 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934082AbaFIWp6 (ORCPT ); Mon, 9 Jun 2014 18:45:58 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Naoya Horiguchi , Andi Kleen , Andrew Morton , Linus Torvalds Subject: [PATCH 3.10 07/40] mm/memory-failure.c: fix memory leak by race between poison and unpoison Date: Mon, 9 Jun 2014 15:48:38 -0700 Message-Id: <20140609224839.448656697@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140609224839.127615063@linuxfoundation.org> References: <20140609224839.127615063@linuxfoundation.org> User-Agent: quilt/0.63-1 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 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Naoya Horiguchi commit 3e030ecc0fc7de10fd0da10c1c19939872a31717 upstream. When a memory error happens on an in-use page or (free and in-use) hugepage, the victim page is isolated with its refcount set to one. When you try to unpoison it later, unpoison_memory() calls put_page() for it twice in order to bring the page back to free page pool (buddy or free hugepage list). However, if another memory error occurs on the page which we are unpoisoning, memory_failure() returns without releasing the refcount which was incremented in the same call at first, which results in memory leak and unconsistent num_poisoned_pages statistics. This patch fixes it. Signed-off-by: Naoya Horiguchi Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/memory-failure.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1153,6 +1153,8 @@ int memory_failure(unsigned long pfn, in */ if (!PageHWPoison(p)) { printk(KERN_ERR "MCE %#lx: just unpoisoned\n", pfn); + atomic_long_sub(nr_pages, &num_poisoned_pages); + put_page(hpage); res = 0; goto out; }