From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f179.google.com (mail-pd0-f179.google.com [209.85.192.179]) by kanga.kvack.org (Postfix) with ESMTP id C11B26B0035 for ; Mon, 30 Jun 2014 20:32:21 -0400 (EDT) Received: by mail-pd0-f179.google.com with SMTP id w10so9061176pde.24 for ; Mon, 30 Jun 2014 17:32:21 -0700 (PDT) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTP id iu6si99598pbc.4.2014.06.30.17.32.20 for ; Mon, 30 Jun 2014 17:32:20 -0700 (PDT) From: Andi Kleen Subject: [PATCH] hwpoison: Fix race with changing page during offlining v2 Date: Mon, 30 Jun 2014 17:32:16 -0700 Message-Id: <1404174736-17480-1-git-send-email-andi@firstfloor.org> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Andi Kleen , Naoya Horiguchi From: Andi Kleen When a hwpoison page is locked it could change state due to parallel modifications. Check after the lock if the page is still the same compound page. [v2: Removed earlier non LRU check which should be already covered elsewhere] Cc: Naoya Horiguchi Signed-off-by: Andi Kleen --- mm/memory-failure.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index cd8989c..99e5077 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1168,6 +1168,16 @@ int memory_failure(unsigned long pfn, int trapno, int flags) lock_page(hpage); /* + * The page could have changed compound pages during the locking. + * If this happens just bail out. + */ + if (compound_head(p) != hpage) { + action_result(pfn, "different compound page after locking", IGNORED); + res = -EBUSY; + goto out; + } + + /* * We use page flags to determine what action should be taken, but * the flags can be modified by the error containment action. One * example is an mlocked page, where PG_mlocked is cleared by -- 1.9.3 -- 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