From: David Rientjes <rientjes@google.com>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Hansen, Dave" <dave.hansen@intel.com>,
"Luck, Tony" <tony.luck@intel.com>, Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm, madvise: Ensure poisoned pages are removed from per-cpu lists
Date: Mon, 28 Aug 2017 13:37:58 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.10.1708281337480.9719@chino.kir.corp.google.com> (raw)
In-Reply-To: <20170828133414.7qro57jbepdcyz5x@techsingularity.net>
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 <wendy.wang@intel.com>
> Cc: stable@kernel.org
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: David Rientjes <rientjes@google.com>
next prev parent reply other threads:[~2017-08-28 20:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-28 13:34 [PATCH] mm, madvise: Ensure poisoned pages are removed from per-cpu lists Mel Gorman
2017-08-28 20:37 ` David Rientjes [this message]
2017-08-29 11:55 ` Vlastimil Babka
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