From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f51.google.com (mail-wg0-f51.google.com [74.125.82.51]) by kanga.kvack.org (Postfix) with ESMTP id 96FF96B0036 for ; Wed, 14 May 2014 11:22:12 -0400 (EDT) Received: by mail-wg0-f51.google.com with SMTP id x13so2100775wgg.10 for ; Wed, 14 May 2014 08:22:11 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTP id ca11si910067wib.94.2014.05.14.08.22.09 for ; Wed, 14 May 2014 08:22:10 -0700 (PDT) From: Naoya Horiguchi Subject: [PATCH] mm/memory-failure.c: fix memory leak by race between poison and unpoison Date: Wed, 14 May 2014 11:21:31 -0400 Message-Id: <1400080891-5145-1-git-send-email-n-horiguchi@ah.jp.nec.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Andi Kleen Cc: Wu Fengguang , linux-kernel@vger.kernel.org, linux-mm@kvack.org 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: [2.6.32+] --- mm/memory-failure.c | 2 ++ 1 file changed, 2 insertions(+) diff --git next-20140512.orig/mm/memory-failure.c next-20140512/mm/memory-failure.c index 9872af1b1e9d..93a08bd78c78 100644 --- next-20140512.orig/mm/memory-failure.c +++ next-20140512/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; } -- 1.9.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org