From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751449Ab3KMXO3 (ORCPT ); Wed, 13 Nov 2013 18:14:29 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:60837 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751085Ab3KMXOW (ORCPT ); Wed, 13 Nov 2013 18:14:22 -0500 From: "Rafael J. Wysocki" To: ACPI Devel Maling List Cc: LKML , Linux PCI , Greg Kroah-Hartman , Bjorn Helgaas , Aaron Lu , Jarkko Nikula , Lan Tianyu , Mika Westerberg , "Luck, Tony" Subject: [PATCH 2/2] ACPI / bind: Use (put|get)_device() on ACPI device objects too Date: Thu, 14 Nov 2013 00:26:47 +0100 Message-ID: <9712243.It8gvaRCs0@vostro.rjw.lan> User-Agent: KMail/4.10.5 (Linux/3.12.0-rc6+; KDE/4.10.5; x86_64; ; ) In-Reply-To: <1803808.ghCmmaO2Cj@vostro.rjw.lan> References: <3268437.YsusHvklcv@vostro.rjw.lan> <1803808.ghCmmaO2Cj@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki When associating a "physical" device with an ACPI device object acpi_bind_one() only uses get_device() to increment the reference counter of the former, but there is no reason not to do that with the latter too. Among other things, that may help to avoid use-after-free when an ACPI device object is freed without calling acpi_unbind_one() for all "physical" devices associated with it (that only can happen in buggy code, but then it's better if the kernel doesn't crash as a result of a bug). For this reason, modify acpi_bind_one() to apply get_device() to the ACPI device object too and update acpi_unbind_one() to drop that reference using put_device() as appropriate. Signed-off-by: Rafael J. Wysocki --- drivers/acpi/glue.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) Index: linux-pm/drivers/acpi/glue.c =================================================================== --- linux-pm.orig/drivers/acpi/glue.c +++ linux-pm/drivers/acpi/glue.c @@ -217,6 +217,7 @@ int acpi_bind_one(struct device *dev, ac if (!acpi_dev) return -EINVAL; + get_device(&acpi_dev->dev); get_device(dev); physical_node = kzalloc(sizeof(*physical_node), GFP_KERNEL); if (!physical_node) { @@ -243,6 +244,7 @@ int acpi_bind_one(struct device *dev, ac goto err; put_device(dev); + put_device(&acpi_dev->dev); return 0; } if (pn->node_id == node_id) { @@ -282,6 +284,7 @@ int acpi_bind_one(struct device *dev, ac err: ACPI_COMPANION_SET(dev, NULL); put_device(dev); + put_device(&acpi_dev->dev); return retval; } EXPORT_SYMBOL_GPL(acpi_bind_one); @@ -307,8 +310,9 @@ int acpi_unbind_one(struct device *dev) sysfs_remove_link(&acpi_dev->dev.kobj, physnode_name); sysfs_remove_link(&dev->kobj, "firmware_node"); ACPI_COMPANION_SET(dev, NULL); - /* acpi_bind_one() increase refcnt by one. */ + /* Drop references taken by acpi_bind_one(). */ put_device(dev); + put_device(&acpi_dev->dev); kfree(entry); break; }