From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f42.google.com (mail-pa0-f42.google.com [209.85.220.42]) by kanga.kvack.org (Postfix) with ESMTP id 85FB16B0038 for ; Fri, 10 Apr 2015 16:39:01 -0400 (EDT) Received: by pacyx8 with SMTP id yx8so32106295pac.1 for ; Fri, 10 Apr 2015 13:39:01 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id gu11si4448813pbd.78.2015.04.10.13.39.00 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 10 Apr 2015 13:39:00 -0700 (PDT) Date: Fri, 10 Apr 2015 13:38:59 -0700 From: Andrew Morton Subject: Re: [PATCH] mm/hugetlb: use pmd_page() in follow_huge_pmd() Message-Id: <20150410133859.fc79985a9514eb1e4d1dcde7@linux-foundation.org> In-Reply-To: <20150410100849.56b9d677@thinkpad> References: <1428595895-24140-1-git-send-email-gerald.schaefer@de.ibm.com> <20150410100849.56b9d677@thinkpad> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Gerald Schaefer Cc: David Rientjes , Naoya Horiguchi , Hugh Dickins , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , Andrea Arcangeli , Martin Schwidefsky , Jiri Slaby On Fri, 10 Apr 2015 10:08:49 +0200 Gerald Schaefer wrote: > On Thu, 9 Apr 2015 12:41:47 -0700 (PDT) > David Rientjes wrote: > > > On Thu, 9 Apr 2015, Gerald Schaefer wrote: > > > > > commit 61f77eda "mm/hugetlb: reduce arch dependent code around > > > follow_huge_*" broke follow_huge_pmd() on s390, where pmd and pte > > > layout differ and using pte_page() on a huge pmd will return wrong > > > results. Using pmd_page() instead fixes this. > > > > > > All architectures that were touched by commit 61f77eda have > > > pmd_page() defined, so this should not break anything on other > > > architectures. > > > > > > Signed-off-by: Gerald Schaefer > > > Cc: stable@vger.kernel.org # v3.12 > > > > Acked-by: David Rientjes > > > > I'm not sure where the stable cc came from, though: commit 61f77eda > > makes s390 use a generic version of follow_huge_pmd() and that > > generic version is buggy for s930 because of commit e66f17ff7177 > > ("mm/hugetlb: take page table lock in follow_huge_pmd()"). Both of > > those are 4.0 material, though, so why is this needed for stable 3.12? > > Both commits 61f77eda and e66f17ff already made it into the 3.12 stable > tree, probably because of SLES 12 (actually that's how I noticed them). > > But I guess I screwed up the stable CC, stable@vger.kernel.org.#.v3.12 > somehow doesn't look right, not sure if the CC in the patch header > suffices. Looks like Jiri Slaby added the patches to 3.12, putting him > on CC now. hm. I think I'll make it Fixes: 61f77eda "mm/hugetlb: reduce arch dependent code around follow_huge_*" ... Cc: There's enough info here for the various tree maintainers to work out whether their kernel needs this fix. -- 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