From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935205AbbCPP5D (ORCPT ); Mon, 16 Mar 2015 11:57:03 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:54714 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755784AbbCPOMS (ORCPT ); Mon, 16 Mar 2015 10:12:18 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Naoya Horiguchi , Andi Kleen , Tony Luck , Chen Gong , Andrew Morton , Linus Torvalds Subject: [PATCH 3.19 040/177] mm: hwpoison: drop lru_add_drain_all() in __soft_offline_page() Date: Mon, 16 Mar 2015 15:07:27 +0100 Message-Id: <20150316140814.935095774@linuxfoundation.org> X-Mailer: git-send-email 2.3.3 In-Reply-To: <20150316140813.085032723@linuxfoundation.org> References: <20150316140813.085032723@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Naoya Horiguchi commit 9ab3b598d2dfbdb0153ffa7e4b1456bbff59a25d upstream. A race condition starts to be visible in recent mmotm, where a PG_hwpoison flag is set on a migration source page *before* it's back in buddy page poo= l. This is problematic because no page flag is supposed to be set when freeing (see __free_one_page().) So the user-visible effect of this race is that it could trigger the BUG_ON() when soft-offlining is called. The root cause is that we call lru_add_drain_all() to make sure that the page is in buddy, but that doesn't work because this function just schedule= s a work item and doesn't wait its completion. drain_all_pages() does drainin= g directly, so simply dropping lru_add_drain_all() solves this problem. Fixes: f15bdfa802bf ("mm/memory-failure.c: fix memory leak in successful soft offlining") Signed-off-by: Naoya Horiguchi Cc: Andi Kleen Cc: Tony Luck Cc: Chen Gong 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 deletions(-) --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1654,8 +1654,6 @@ static int __soft_offline_page(struct pa * setting PG_hwpoison. */ if (!is_free_buddy_page(page)) - lru_add_drain_all(); - if (!is_free_buddy_page(page)) drain_all_pages(page_zone(page)); SetPageHWPoison(page); if (!is_free_buddy_page(page))