Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754197AbaFWNEJ (ORCPT ); Mon, 23 Jun 2014 09:04:09 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:36805 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753799AbaFWND5 (ORCPT ); Mon, 23 Jun 2014 09:03:57 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Naoya Horiguchi , Andi Kleen , Andrew Morton , Linus Torvalds , Luis Henriques Subject: [PATCH 3.11 20/93] mm/memory-failure.c: fix memory leak by race between poison and unpoison Date: Mon, 23 Jun 2014 14:01:59 +0100 Message-Id: <1403528592-2163-21-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1403528592-2163-1-git-send-email-luis.henriques@canonical.com> References: <1403528592-2163-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.12 -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: Luis Henriques --- mm/memory-failure.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index d3772a6118ee..9a5150d2e937 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1153,6 +1153,8 @@ int memory_failure(unsigned long pfn, int trapno, int flags) */ 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; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/