From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752115AbcDUIty (ORCPT ); Thu, 21 Apr 2016 04:49:54 -0400 Received: from foss.arm.com ([217.140.101.70]:53056 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751552AbcDUItv (ORCPT ); Thu, 21 Apr 2016 04:49:51 -0400 Date: Thu, 21 Apr 2016 09:49:46 +0100 From: Catalin Marinas To: "Shi, Yang" Cc: Will Deacon , linux-mm@kvack.org, LKML , "linux-arm-kernel@lists.infradead.org" Subject: Re: [BUG] set_pte_at: racy dirty state clearing warning Message-ID: <20160421084946.GA23774@e104818-lin.cambridge.arm.com> References: <57180A53.3000207@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57180A53.3000207@linaro.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 20, 2016 at 04:01:39PM -0700, Shi, Yang wrote: > When I enable memory comact via > > # echo 1 > /proc/sys/vm/compact_memory > > I got the below WARNING: > > set_pte_at: racy dirty state clearing: 0x0068000099371bd3 -> > 0x0068000099371fd3 > ------------[ cut here ]------------ > WARNING: CPU: 5 PID: 294 at ./arch/arm64/include/asm/pgtable.h:227 > ptep_set_access_flags+0x138/0x1b8 > Modules linked in: Do you have this patch applied: http://article.gmane.org/gmane.linux.ports.arm.kernel/492239 It's also queued into -next as commit 66dbd6e61a52. > My kernel has ARM64_HW_AFDBM enabled, but LS2085 is not ARMv8.1. > > The code shows it just check if ARM64_HW_AFDBM is enabled or not, but > doesn't check if the CPU really has such capability. > > So, it might be better to have the capability checked runtime? The warnings are there to spot any incorrect uses of the pte accessors even before you run on AF/DBM-capable hardware. -- Catalin