From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre-Louis Bossart Subject: Re: [PATCH] ACPI / property: fix handling of data_nodes in acpi_get_next_subnode() Date: Tue, 30 Apr 2019 11:41:50 -0500 Message-ID: References: <20190430155229.14213-1-pierre-louis.bossart@linux.intel.com> <20190430163041.GN9224@smile.fi.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190430163041.GN9224@smile.fi.intel.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Andy Shevchenko 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 4/30/19 11:30 AM, Andy Shevchenko wrote: > 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. Thanks Andy for the review. I hesitated to add a fixes tag. The line about resetting the adev pointer was indeed removed in the latter commit, but there were a slew of other changes done later by Sakari on hierarchical _DSD so it's quite complicated to say when this was last fully functional. > > 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 >> > 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=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 D3120C43219 for ; Tue, 30 Apr 2019 16:41:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD46A20652 for ; Tue, 30 Apr 2019 16:41:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726048AbfD3Qlz (ORCPT ); Tue, 30 Apr 2019 12:41:55 -0400 Received: from mga06.intel.com ([134.134.136.31]:28899 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726006AbfD3Qly (ORCPT ); Tue, 30 Apr 2019 12:41:54 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Apr 2019 09:41:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,414,1549958400"; d="scan'208";a="153624424" Received: from linux.intel.com ([10.54.29.200]) by FMSMGA003.fm.intel.com with ESMTP; 30 Apr 2019 09:41:53 -0700 Received: from brettjgr-mobl1.ger.corp.intel.com (unknown [10.254.180.216]) by linux.intel.com (Postfix) with ESMTP id 6D07E5803DA; Tue, 30 Apr 2019 09:41:52 -0700 (PDT) Subject: Re: [PATCH] ACPI / property: fix handling of data_nodes in acpi_get_next_subnode() To: Andy Shevchenko Cc: linux-acpi@vger.kernel.org, "Rafael J . Wysocki" , Len Brown , linux-kernel@vger.kernel.org, Mika Westerberg References: <20190430155229.14213-1-pierre-louis.bossart@linux.intel.com> <20190430163041.GN9224@smile.fi.intel.com> From: Pierre-Louis Bossart Message-ID: Date: Tue, 30 Apr 2019 11:41:50 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190430163041.GN9224@smile.fi.intel.com> Content-Type: text/plain; charset="UTF-8"; format="flowed" Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Message-ID: <20190430164150.kjS-Or05uftqBQGlUYvXed9HVP35J6-t0EXc37o30w8@z> On 4/30/19 11:30 AM, Andy Shevchenko wrote: > 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. Thanks Andy for the review. I hesitated to add a fixes tag. The line about resetting the adev pointer was indeed removed in the latter commit, but there were a slew of other changes done later by Sakari on hierarchical _DSD so it's quite complicated to say when this was last fully functional. > > 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 >> >