From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f199.google.com (mail-wr0-f199.google.com [209.85.128.199]) by kanga.kvack.org (Postfix) with ESMTP id 2DD5E6B0292 for ; Mon, 28 Aug 2017 09:34:17 -0400 (EDT) Received: by mail-wr0-f199.google.com with SMTP id p37so713582wrc.5 for ; Mon, 28 Aug 2017 06:34:17 -0700 (PDT) Received: from outbound-smtp09.blacknight.com (outbound-smtp09.blacknight.com. [46.22.139.14]) by mx.google.com with ESMTPS id 89si364994edq.95.2017.08.28.06.34.15 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Aug 2017 06:34:15 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail02.blacknight.ie [81.17.254.11]) by outbound-smtp09.blacknight.com (Postfix) with ESMTPS id 8A10C1C1969 for ; Mon, 28 Aug 2017 14:34:15 +0100 (IST) Date: Mon, 28 Aug 2017 14:34:15 +0100 From: Mel Gorman Subject: [PATCH] mm, madvise: Ensure poisoned pages are removed from per-cpu lists Message-ID: <20170828133414.7qro57jbepdcyz5x@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: "Hansen, Dave" , "Luck, Tony" , Linux MM , LKML Wendy Wang reported off-list that a RAS HWPOISON-SOFT test case failed and bisected it to the commit 479f854a207c ("mm, page_alloc: defer debugging checks of pages allocated from the PCP"). The problem is that a page that was poisoned with madvise() is reused. The commit removed a check that would trigger if DEBUG_VM was enabled but re-enabling the check only fixes the problem as a side-effect by printing a bad_page warning and recovering. The root of the problem is that a madvise() can leave a poisoned on the per-cpu list. This patch drains all per-cpu lists after pages are poisoned so that they will not be reused. Wendy reports that the test case in question passes with this patch applied. While this could be done in a targeted fashion, it is over-complicated for such a rare operation. Fixes: 479f854a207c ("mm, page_alloc: defer debugging checks of pages allocated from the PCP") Reported-and-tested-by: Wang, Wendy Cc: stable@kernel.org Signed-off-by: Mel Gorman --- mm/madvise.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/madvise.c b/mm/madvise.c index 23ed525bc2bc..4d7d1e5ddba9 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -613,6 +613,7 @@ static int madvise_inject_error(int behavior, unsigned long start, unsigned long end) { struct page *page; + struct zone *zone; if (!capable(CAP_SYS_ADMIN)) return -EPERM; @@ -646,6 +647,11 @@ static int madvise_inject_error(int behavior, if (ret) return ret; } + + /* Ensure that all poisoned pages are removed from per-cpu lists */ + for_each_populated_zone(zone) + drain_all_pages(zone); + return 0; } #endif -- 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