From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966480AbaFQVtz (ORCPT ); Tue, 17 Jun 2014 17:49:55 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:54255 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966443AbaFQVtu (ORCPT ); Tue, 17 Jun 2014 17:49:50 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Naoya Horiguchi , Andi Kleen , Andrew Morton , Linus Torvalds , Kamal Mostafa Subject: [PATCH 3.13 162/212] mm/memory-failure.c: fix memory leak by race between poison and unpoison Date: Tue, 17 Jun 2014 14:44:16 -0700 Message-Id: <1403041506-13646-163-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1403041506-13646-1-git-send-email-kamal@canonical.com> References: <1403041506-13646-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11.4 -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: Kamal Mostafa --- mm/memory-failure.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index b22effc..3b0855b 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1157,6 +1157,8 @@ 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