From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161251Ab2JXWEd (ORCPT ); Wed, 24 Oct 2012 18:04:33 -0400 Received: from ogre.sisk.pl ([193.178.161.156]:35687 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758746Ab2JXWEb (ORCPT ); Wed, 24 Oct 2012 18:04:31 -0400 From: "Rafael J. Wysocki" To: Toshi Kani Cc: Yasuaki Ishimatsu , linux-acpi@vger.kernel.org, lenb@kernel.org, linux-kernel@vger.kernel.org, liuj97@gmail.com Subject: Re: [PATCH 1/2] ACPI: Fix stale pointer access to flags.lockable Date: Thu, 25 Oct 2012 00:08:26 +0200 Message-ID: <1588310.r9ljFmyoH6@vostro.rjw.lan> User-Agent: KMail/4.8.5 (Linux/3.6.2-6-desktop; KDE/4.8.5; x86_64; ; ) In-Reply-To: <1350482142.28185.0.camel@misato.fc.hp.com> References: <1350318870-5700-1-git-send-email-toshi.kani@hp.com> <507E090C.2070607@jp.fujitsu.com> <1350482142.28185.0.camel@misato.fc.hp.com> 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 On Wednesday 17 of October 2012 07:55:42 Toshi Kani wrote: > On Wed, 2012-10-17 at 10:25 +0900, Yasuaki Ishimatsu wrote: > > 2012/10/16 1:34, Toshi Kani wrote: > > > During hot-remove, acpi_bus_hot_remove_device() calls ACPI _LCK > > > method when device->flags.lockable is set. However, this device > > > pointer is stale since the target acpi_device object has been > > > already kfree'd by acpi_bus_trim(). > > > > > > The flags.lockable indicates whether or not this ACPI object > > > implements _LCK method. Fix the stable pointer access by replacing > > > it with acpi_get_handle() to check if _LCK is implemented. > > > > > > Signed-off-by: Toshi Kani > > > > Looks good to me. > > Reviewed-by: Yasuaki Ishimatsu > > Thanks Yasuaki for reviewing! Applied to linux-pm.git/linux-next as v3.8 material. Thanks, Rafael > > > --- > > > drivers/acpi/scan.c | 6 +++++- > > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > > > index 1fcb867..ed87f43 100644 > > > --- a/drivers/acpi/scan.c > > > +++ b/drivers/acpi/scan.c > > > @@ -97,6 +97,7 @@ void acpi_bus_hot_remove_device(void *context) > > > struct acpi_eject_event *ej_event = (struct acpi_eject_event *) context; > > > struct acpi_device *device; > > > acpi_handle handle = ej_event->handle; > > > + acpi_handle temp; > > > struct acpi_object_list arg_list; > > > union acpi_object arg; > > > acpi_status status = AE_OK; > > > @@ -117,13 +118,16 @@ void acpi_bus_hot_remove_device(void *context) > > > goto err_out; > > > } > > > > > > + /* device has been freed */ > > > + device = NULL; > > > + > > > /* power off device */ > > > status = acpi_evaluate_object(handle, "_PS3", NULL, NULL); > > > if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) > > > printk(KERN_WARNING PREFIX > > > "Power-off device failed\n"); > > > > > > - if (device->flags.lockable) { > > > + if (ACPI_SUCCESS(acpi_get_handle(handle, "_LCK", &temp))) { > > > arg_list.count = 1; > > > arg_list.pointer = &arg; > > > arg.type = ACPI_TYPE_INTEGER; > > > > > > > > > > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.