From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756065AbbFOVSc (ORCPT ); Mon, 15 Jun 2015 17:18:32 -0400 Received: from mail-wi0-f177.google.com ([209.85.212.177]:34688 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752714AbbFOVSU (ORCPT ); Mon, 15 Jun 2015 17:18:20 -0400 Date: Mon, 15 Jun 2015 23:18:16 +0200 From: Michal Hocko To: Pali =?iso-8859-1?Q?Roh=E1r?= Cc: Hans de Goede , Darren Hart , Ben Skeggs , Stuart Hayes , Matthew Garrett , Andrew Morton , platform-driver-x86@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: Possible broken MM code in dell-laptop.c? Message-ID: <20150615211816.GC16138@dhcp22.suse.cz> References: <201506141105.07171@pali> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <201506141105.07171@pali> 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 Sun 14-06-15 11:05:07, Pali Rohár wrote: > Hello, > > in drivers/platform/x86/dell-laptop.c is this part of code: > > static int __init dell_init(void) > { > ... > /* > * Allocate buffer below 4GB for SMI data--only 32-bit physical addr > * is passed to SMI handler. > */ > bufferpage = alloc_page(GFP_KERNEL | GFP_DMA32); [...] > buffer = page_address(bufferpage); [...] > fail_rfkill: > free_page((unsigned long)bufferpage); This one should be __free_page because it consumes struct page* and it is the proper counter part for alloc_page. free_page, just to make it confusing, consumes an address which has to be translated to a struct page. I have no idea why the API has been done this way and yeah, it is really confusing. [...] > static void __exit dell_exit(void) > { > ... > free_page((unsigned long)buffer); -- Michal Hocko SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: Possible broken MM code in dell-laptop.c? Date: Mon, 15 Jun 2015 23:18:16 +0200 Message-ID: <20150615211816.GC16138@dhcp22.suse.cz> References: <201506141105.07171@pali> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <201506141105.07171@pali> Sender: owner-linux-mm@kvack.org To: Pali =?iso-8859-1?Q?Roh=E1r?= Cc: Hans de Goede , Darren Hart , Ben Skeggs , Stuart Hayes , Matthew Garrett , Andrew Morton , platform-driver-x86@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-Id: platform-driver-x86.vger.kernel.org On Sun 14-06-15 11:05:07, Pali Roh=E1r wrote: > Hello, >=20 > in drivers/platform/x86/dell-laptop.c is this part of code: >=20 > static int __init dell_init(void) > { > ... > /* > * Allocate buffer below 4GB for SMI data--only 32-bit physical addr > * is passed to SMI handler. > */ > bufferpage =3D alloc_page(GFP_KERNEL | GFP_DMA32); [...] > buffer =3D page_address(bufferpage); [...] > fail_rfkill: > free_page((unsigned long)bufferpage); This one should be __free_page because it consumes struct page* and it is the proper counter part for alloc_page. free_page, just to make it confusing, consumes an address which has to be translated to a struct page. I have no idea why the API has been done this way and yeah, it is really confusing. [...] > static void __exit dell_exit(void) > { > ... > free_page((unsigned long)buffer); --=20 Michal Hocko SUSE Labs -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f182.google.com (mail-wi0-f182.google.com [209.85.212.182]) by kanga.kvack.org (Postfix) with ESMTP id 7AC246B0038 for ; Mon, 15 Jun 2015 17:18:21 -0400 (EDT) Received: by wifx6 with SMTP id x6so964022wif.0 for ; Mon, 15 Jun 2015 14:18:20 -0700 (PDT) Received: from mail-wg0-x22e.google.com (mail-wg0-x22e.google.com. [2a00:1450:400c:c00::22e]) by mx.google.com with ESMTPS id u7si20320619wiw.120.2015.06.15.14.18.19 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 15 Jun 2015 14:18:19 -0700 (PDT) Received: by wgv5 with SMTP id 5so78647602wgv.1 for ; Mon, 15 Jun 2015 14:18:19 -0700 (PDT) Date: Mon, 15 Jun 2015 23:18:16 +0200 From: Michal Hocko Subject: Re: Possible broken MM code in dell-laptop.c? Message-ID: <20150615211816.GC16138@dhcp22.suse.cz> References: <201506141105.07171@pali> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <201506141105.07171@pali> Sender: owner-linux-mm@kvack.org List-ID: To: Pali =?iso-8859-1?Q?Roh=E1r?= Cc: Hans de Goede , Darren Hart , Ben Skeggs , Stuart Hayes , Matthew Garrett , Andrew Morton , platform-driver-x86@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Sun 14-06-15 11:05:07, Pali Rohar wrote: > Hello, > > in drivers/platform/x86/dell-laptop.c is this part of code: > > static int __init dell_init(void) > { > ... > /* > * Allocate buffer below 4GB for SMI data--only 32-bit physical addr > * is passed to SMI handler. > */ > bufferpage = alloc_page(GFP_KERNEL | GFP_DMA32); [...] > buffer = page_address(bufferpage); [...] > fail_rfkill: > free_page((unsigned long)bufferpage); This one should be __free_page because it consumes struct page* and it is the proper counter part for alloc_page. free_page, just to make it confusing, consumes an address which has to be translated to a struct page. I have no idea why the API has been done this way and yeah, it is really confusing. [...] > static void __exit dell_exit(void) > { > ... > free_page((unsigned long)buffer); -- Michal Hocko SUSE Labs -- 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