From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754700AbbCaUFS (ORCPT ); Tue, 31 Mar 2015 16:05:18 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:39498 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753549AbbCaTuA (ORCPT ); Tue, 31 Mar 2015 15:50:00 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Naoya Horiguchi , Andi Kleen , Tony Luck , Chen Gong , Andrew Morton , Linus Torvalds , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 096/143] mm: hwpoison: drop lru_add_drain_all() in __soft_offline_page() Date: Tue, 31 Mar 2015 12:47:41 -0700 Message-Id: <1427831308-1854-97-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1427831308-1854-1-git-send-email-kamal@canonical.com> References: <1427831308-1854-1-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-ckt18 -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: Kamal Mostafa --- mm/memory-failure.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index ba1ab14..112be59f 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1639,8 +1639,6 @@ static int __soft_offline_page(struct page *page, int flags) * setting PG_hwpoison. */ if (!is_free_buddy_page(page)) - lru_add_drain_all(); - if (!is_free_buddy_page(page)) drain_all_pages(); SetPageHWPoison(page); if (!is_free_buddy_page(page)) -- 1.9.1