From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52164C4321D for ; Mon, 20 Aug 2018 19:12:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 19E7A21735 for ; Mon, 20 Aug 2018 19:12:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 19E7A21735 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726683AbeHTW3p (ORCPT ); Mon, 20 Aug 2018 18:29:45 -0400 Received: from mx2.suse.de ([195.135.220.15]:35106 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726077AbeHTW3p (ORCPT ); Mon, 20 Aug 2018 18:29:45 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 4ACF1AEBD; Mon, 20 Aug 2018 19:12:54 +0000 (UTC) Date: Mon, 20 Aug 2018 21:12:52 +0200 From: Michal Hocko To: Andi Kleen Cc: Guenter Roeck , linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Linus Torvalds , Thomas Gleixner , Josh Poimboeuf , Dave Hansen , David Woodhouse , x86@kernel.org, dvyukov@google.com, hughd@google.com, "Kirill A. Shutemov" , Andrea Arcangeli Subject: Re: Crash in MM code in v4.4.y, v4.9.y with TRANSPARENT_HUGEPAGE enabled Message-ID: <20180820191252.GS29735@dhcp22.suse.cz> References: <20180817222733.GA18575@roeck-us.net> <20180820162938.GR29735@dhcp22.suse.cz> <20180820180353.GO12066@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180820180353.GO12066@tassilo.jf.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 20-08-18 11:03:53, Andi Kleen wrote: > On Mon, Aug 20, 2018 at 06:29:38PM +0200, Michal Hocko wrote: > > On Fri 17-08-18 15:27:33, Guenter Roeck wrote: > > > Hi, > > > > > > the following crash is seen in v4.4.148, v4.4.149, v4.9.120, and v4.9.121 > > > with CONFIG_TRANSPARENT_HUGEPAGE=y, CONFIG_TRANSPARENT_HUGEPAGE_MADVISE=y. > > > > Could you try to apply fd7e315988b7 ("x86/mm: Simplify p[g4um]d_page() > > macros"). I do not see it in stable 4.4 tree and it has been introduced > > much later in 4.14. This one gave us quite some headache because it is > > soooo easy to overlook. > > Good catch! > > I tested that with 4.9 and backporting the patch indeed fixes the > syzcaller test case running in a KVM VM. Backported patch appended. > > Should probably go into 4.4 and 4.9. > > Cannot explain the 4.17 report unfortunately. I haven't seen that one yet and likely won't get to it tomorrow as well but I would start looking for a direct pte_val usage. We have had som out of tree xen code which was doing exactly this. Not really easy to find by a code inspection. -- Michal Hocko SUSE Labs