From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: [PATCH] ACPI / property: fix handling of data_nodes in acpi_get_next_subnode() Date: Tue, 30 Apr 2019 19:30:41 +0300 Message-ID: <20190430163041.GN9224@smile.fi.intel.com> References: <20190430155229.14213-1-pierre-louis.bossart@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190430155229.14213-1-pierre-louis.bossart@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Pierre-Louis Bossart Cc: linux-acpi@vger.kernel.org, "Rafael J . Wysocki" , Len Brown , linux-kernel@vger.kernel.org, Mika Westerberg List-Id: linux-acpi@vger.kernel.org On Tue, Apr 30, 2019 at 10:52:29AM -0500, Pierre-Louis Bossart wrote: > When the DSDT tables expose devices with subdevices and a set of > hierarchical _DSD properties, the data returned by > acpi_get_next_subnode() is incorrect, with the results suggesting a bad > pointer assignment. The parser works fine with device_nodes or > data_nodes, but not with a combination of the two. > > The problem is traced to an invalid pointer used when jumping from > handling device_nodes to data nodes. The existing code looks for data > nodes below the last subdevice found instead of the common root. Fix > by forcing the acpi_device pointer to be derived from the same fwnode > for the two types of subnodes. > > This same problem of handling device and data nodes was already fixed > in a similar way by 'commit bf4703fdd166 ("ACPI / property: fix data > node parsing in acpi_get_next_subnode()")' but broken later by 'commit > 34055190b19 ("ACPI / property: Add fwnode_get_next_child_node()")', so > this should probably go to linux-stable all the way to 4.12 Period is missed in above sentence. I think it make sense to add Fixes: tag. Nevertheless, Reviewed-by: Andy Shevchenko Thank you for fixing this interesting issue! > > Signed-off-by: Pierre-Louis Bossart > --- > drivers/acpi/property.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c > index 5815356ea6ad..efc74f912f39 100644 > --- a/drivers/acpi/property.c > +++ b/drivers/acpi/property.c > @@ -943,6 +943,16 @@ struct fwnode_handle *acpi_get_next_subnode(const struct fwnode_handle *fwnode, > const struct acpi_data_node *data = to_acpi_data_node(fwnode); > struct acpi_data_node *dn; > > + /* > + * We can have a combination of device and data nodes, > + * e.g. with hierarchical _DSD properties. Make sure > + * the adev pointer is restored before going through > + * data nodes, otherwise we will be looking for > + * data_nodes below the last device found instead of > + * the common fwnode shared by device_nodes and > + * data_nodes > + */ > + adev = to_acpi_device_node(fwnode); > if (adev) > head = &adev->data.subnodes; > else if (data) > -- > 2.17.1 > -- With Best Regards, Andy Shevchenko 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=-8.4 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=unavailable 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 585A1C43219 for ; Tue, 30 Apr 2019 16:30:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3391C20644 for ; Tue, 30 Apr 2019 16:30:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726602AbfD3Qao (ORCPT ); Tue, 30 Apr 2019 12:30:44 -0400 Received: from mga03.intel.com ([134.134.136.65]:11907 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726102AbfD3Qao (ORCPT ); Tue, 30 Apr 2019 12:30:44 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Apr 2019 09:30:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,414,1549958400"; d="scan'208";a="342198148" Received: from smile.fi.intel.com (HELO smile) ([10.237.72.86]) by fmsmga006.fm.intel.com with ESMTP; 30 Apr 2019 09:30:42 -0700 Received: from andy by smile with local (Exim 4.92) (envelope-from ) id 1hLVeT-0007p9-4i; Tue, 30 Apr 2019 19:30:41 +0300 Date: Tue, 30 Apr 2019 19:30:41 +0300 From: Andy Shevchenko To: Pierre-Louis Bossart Cc: linux-acpi@vger.kernel.org, "Rafael J . Wysocki" , Len Brown , linux-kernel@vger.kernel.org, Mika Westerberg Subject: Re: [PATCH] ACPI / property: fix handling of data_nodes in acpi_get_next_subnode() Message-ID: <20190430163041.GN9224@smile.fi.intel.com> References: <20190430155229.14213-1-pierre-louis.bossart@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <20190430155229.14213-1-pierre-louis.bossart@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Message-ID: <20190430163041.Hb7H2qEnu8wv1dZogSBJZnDFBdsJBGw6WW8kSvPfDjQ@z> On Tue, Apr 30, 2019 at 10:52:29AM -0500, Pierre-Louis Bossart wrote: > When the DSDT tables expose devices with subdevices and a set of > hierarchical _DSD properties, the data returned by > acpi_get_next_subnode() is incorrect, with the results suggesting a bad > pointer assignment. The parser works fine with device_nodes or > data_nodes, but not with a combination of the two. > > The problem is traced to an invalid pointer used when jumping from > handling device_nodes to data nodes. The existing code looks for data > nodes below the last subdevice found instead of the common root. Fix > by forcing the acpi_device pointer to be derived from the same fwnode > for the two types of subnodes. > > This same problem of handling device and data nodes was already fixed > in a similar way by 'commit bf4703fdd166 ("ACPI / property: fix data > node parsing in acpi_get_next_subnode()")' but broken later by 'commit > 34055190b19 ("ACPI / property: Add fwnode_get_next_child_node()")', so > this should probably go to linux-stable all the way to 4.12 Period is missed in above sentence. I think it make sense to add Fixes: tag. Nevertheless, Reviewed-by: Andy Shevchenko Thank you for fixing this interesting issue! > > Signed-off-by: Pierre-Louis Bossart > --- > drivers/acpi/property.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c > index 5815356ea6ad..efc74f912f39 100644 > --- a/drivers/acpi/property.c > +++ b/drivers/acpi/property.c > @@ -943,6 +943,16 @@ struct fwnode_handle *acpi_get_next_subnode(const struct fwnode_handle *fwnode, > const struct acpi_data_node *data = to_acpi_data_node(fwnode); > struct acpi_data_node *dn; > > + /* > + * We can have a combination of device and data nodes, > + * e.g. with hierarchical _DSD properties. Make sure > + * the adev pointer is restored before going through > + * data nodes, otherwise we will be looking for > + * data_nodes below the last device found instead of > + * the common fwnode shared by device_nodes and > + * data_nodes > + */ > + adev = to_acpi_device_node(fwnode); > if (adev) > head = &adev->data.subnodes; > else if (data) > -- > 2.17.1 > -- With Best Regards, Andy Shevchenko