From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757791Ab3BSCjJ (ORCPT ); Mon, 18 Feb 2013 21:39:09 -0500 Received: from smtp.nue.novell.com ([195.135.221.5]:53104 "EHLO smtp.nue.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757003Ab3BSCjI (ORCPT ); Mon, 18 Feb 2013 21:39:08 -0500 Subject: Re: [PATCH] acer-wmi: do not use 'devices' uninitialized From: joeyli To: Paul Bolle Cc: Matthew Garrett , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <1359033178.1325.15.camel@x61.thuisdomein> References: <1359033178.1325.15.camel@x61.thuisdomein> Content-Type: text/plain; charset="UTF-8" Date: Tue, 19 Feb 2013 10:38:14 +0800 Message-ID: <1361241494.6635.2.camel@linux-s257.site> Mime-Version: 1.0 X-Mailer: Evolution 2.28.2 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Paul, Sorry for I am late to reply your patch. 於 四，2013-01-24 於 14:12 +0100，Paul Bolle 提到： > Commit f20aaba9819d0801fb1314363f97239da0100bac ("acer-wmi: fix obj is > NULL but dereferenced") introduced a GCC warning: > drivers/platform/x86/acer-wmi.c: In function ‘acer_wmi_init’: > drivers/platform/x86/acer-wmi.c:1216:14: warning: ‘devices’ may be used uninitialized in this function [-Wmaybe-uninitialized] > drivers/platform/x86/acer-wmi.c:1193:6: note: ‘devices’ was declared here > > GCC is correct. In WMID_set_capabilities() there are now clearly codepaths > that use 'devices' uninitialized. (WMID_set_capabilities() is apparently > inlined in acer_wmi_init().) Previously that couldn't happen. So rework > the code to use the previous logic, but also make sure 'obj' will not be > dereferenced while NULL. > > Signed-off-by: Paul Bolle Zhang Rui sent similar patch for fix the warning: http://www.mail-archive.com/platform-driver-x86@vger.kernel.org/msg04016.html Still appreciate for your contribution! Thanks a lot! Joey Lee > --- > Compile tested only! > > drivers/platform/x86/acer-wmi.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c > index afed701..0ddac19 100644 > --- a/drivers/platform/x86/acer-wmi.c > +++ b/drivers/platform/x86/acer-wmi.c > @@ -1197,14 +1197,12 @@ static acpi_status WMID_set_capabilities(void) > return status; > > obj = (union acpi_object *) out.pointer; > - if (obj) { > - if (obj->type == ACPI_TYPE_BUFFER && > + if (obj && obj->type == ACPI_TYPE_BUFFER && > (obj->buffer.length == sizeof(u32) || > obj->buffer.length == sizeof(u64))) { > devices = *((u32 *) obj->buffer.pointer); > - } else if (obj->type == ACPI_TYPE_INTEGER) { > + } else if (obj && obj->type == ACPI_TYPE_INTEGER) { > devices = (u32) obj->integer.value; > - } > } else { > kfree(out.pointer); > return AE_ERROR;