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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 44E81C433E0 for ; Thu, 18 Mar 2021 23:09:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED72964E42 for ; Thu, 18 Mar 2021 23:09:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231979AbhCRXJC (ORCPT ); Thu, 18 Mar 2021 19:09:02 -0400 Received: from mga03.intel.com ([134.134.136.65]:14147 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232539AbhCRXIk (ORCPT ); Thu, 18 Mar 2021 19:08:40 -0400 IronPort-SDR: JGHBRoTEFUx8mkhEbPIUKxsSBQtB5SDdpgA54FT1JfG6x/6+JhLsq0YFlE/Vh9RozY1ZJUQQ9e az/4sNEkMlDQ== X-IronPort-AV: E=McAfee;i="6000,8403,9927"; a="189826070" X-IronPort-AV: E=Sophos;i="5.81,259,1610438400"; d="scan'208";a="189826070" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Mar 2021 16:08:40 -0700 IronPort-SDR: qLoEcnaesFvw5IGzJERhBclTOxZS9bIOB+4zBC4xbfhYL+Gt2iT6TaQs0aobO13c0V0w1otsNU VgR23RfyA60A== X-IronPort-AV: E=Sophos;i="5.81,259,1610438400"; d="scan'208";a="406547310" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Mar 2021 16:08:39 -0700 Date: Thu, 18 Mar 2021 16:08:39 -0700 From: Ira Weiny To: Thomas Gleixner Cc: Oliver Sang , Chaitanya Kulkarni , David Sterba , Andrew Morton , "hch@infradead.org" , Christoph Hellwig , LKML , "lkp@lists.01.org" , "lkp@intel.com" , Xing Zhengjun Subject: Re: [mm/highmem] 61b205f579: WARNING:at_mm/highmem.c:#__kmap_local_sched_out Message-ID: <20210318230839.GY3014244@iweiny-DESK2.sc.intel.com> References: <20210304083825.GB17830@xsang-OptiPlex-9020> <20210311160220.GS3014244@iweiny-DESK2.sc.intel.com> <20210312062755.GA5022@xsang-OptiPlex-9020> <20210316073756.GQ3014244@iweiny-DESK2.sc.intel.com> <87blbhzygm.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87blbhzygm.fsf@nanos.tec.linutronix.de> User-Agent: Mutt/1.11.1 (2018-12-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 17, 2021 at 02:44:41PM +0100, Thomas Gleixner wrote: > On Tue, Mar 16 2021 at 00:37, Ira Weiny wrote: > > > > I think I see the issue. I think this is an invalid configuration. > > > > 00:26:43 > grep DEBUG_KMAP config-5.11.0-rc7-00002-g61b205f57991 > > CONFIG_DEBUG_KMAP_LOCAL=y > > CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP=y > > > > 00:26:48 > grep DEBUG_HIGHMEM config-5.11.0-rc7-00002-g61b205f57991 > > # CONFIG_DEBUG_HIGHMEM is not set > > No. It's valid so you can test that crap on 64bit. > > > DEBUG_KMAP_LOCAL causes guard pages to be added to the kmap_ctrl array. But > > DEBUG_HIGHMEM is used in __kmap_local_sched_out() to check the guard pages. > > > > DEBUG_HIGHMEM is supposed to select DEBUG_KMAP_LOCAL... but apparently that > > did not happen when this configuration was made. > > > > I still have not hit this condition in my testing. Could you ensure that > > DEBUG_HIGMEM is set and rerun the test to see if I am correct? > > Why? The whole point of CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP is to allow > testing of this kmap_local/atomic stuff w/o HIGHMEM, e.g. on 64 bit. Ok yea I was looking at this backwards. > > > Thomas wouldn't the following enable checks make more sense? Or perhaps be > > more consistent with the processing of kmap_ctrl? > > Neither nor. It's simply required to make DEBUG_KMAP_LOCAL=y && > HIGHMEM=n case work. > > Please add: > Fixes: 0e91a0c6984c ("mm/highmem: Provide CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP") > Patch sent. Thanks for setting me straight, Ira