From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id D33346B02B4 for ; Mon, 28 Aug 2017 16:38:01 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id r133so2373077pgr.6 for ; Mon, 28 Aug 2017 13:38:01 -0700 (PDT) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id r138sor814119pgr.165.2017.08.28.13.38.00 for (Google Transport Security); Mon, 28 Aug 2017 13:38:00 -0700 (PDT) Date: Mon, 28 Aug 2017 13:37:58 -0700 (PDT) From: David Rientjes Subject: Re: [PATCH] mm, madvise: Ensure poisoned pages are removed from per-cpu lists In-Reply-To: <20170828133414.7qro57jbepdcyz5x@techsingularity.net> Message-ID: References: <20170828133414.7qro57jbepdcyz5x@techsingularity.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Andrew Morton , "Hansen, Dave" , "Luck, Tony" , Linux MM , LKML On Mon, 28 Aug 2017, Mel Gorman wrote: > 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 Acked-by: David Rientjes -- 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