From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755909AbYEHGF5 (ORCPT ); Thu, 8 May 2008 02:05:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758733AbYEHGFb (ORCPT ); Thu, 8 May 2008 02:05:31 -0400 Received: from rv-out-0506.google.com ([209.85.198.231]:45363 "EHLO rv-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758604AbYEHGF1 (ORCPT ); Thu, 8 May 2008 02:05:27 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=uUHgzTpPF4V2yLynEhIh7SwomgK+Nku87rjwlUZNxMYEZWDg0s2gt+37Ed/kKX/L2sEjvYdFxvju/8neZl6aGur2w6AwGLDg1HkrId6fpBxHeF++LCGkQWR4SjuoCpMVMzmNZu1dGBdp271HJRXuIbkJsVHhhIk6/rYN6ThuaP4= Message-ID: <19f34abd0805072305i19dc37bn3e13fbca4b6981e3@mail.gmail.com> Date: Thu, 8 May 2008 08:05:27 +0200 From: "Vegard Nossum" To: "Lin Ming" Subject: Re: ACPI: kmemcheck: Caught 16-bit read from freed memory (f7c12ec6) Cc: "Pekka Enberg" , "Bob Moore" , "Alexey Starikovskiy" , "Len Brown" , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <1210224923.22503.8.camel@minggr.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <19f34abd0805060909q635d2d43j9414e5f179c9e22f@mail.gmail.com> <84144f020805061338yd6e3declaf5ff9ca344c28ba@mail.gmail.com> <19f34abd0805061346q4af7e4f8kd65009f8d3021d0e@mail.gmail.com> <4820C56C.6070204@cs.helsinki.fi> <19f34abd0805071221o236c8629ib184a4720f178e7b@mail.gmail.com> <1210224923.22503.8.camel@minggr.sh.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Thu, May 8, 2008 at 7:35 AM, Lin Ming wrote: > Here comes a simple patch that fixes the warning in my machine. > > Vegard, would you please help to test it in your machine? > Thanks for the try, but unfortunately this does not solve the problem. Please note that kmemcheck is an patch to the kernel; without it you will never see the warning. You can pull it from git://git.kernel.org/pub/scm/linux/kernel/git/vegard/kmemcheck.git current though it is unlikely that it will help you more than looking at the code (or the report) will do. > Thanks, > Lin Ming > > Signed-off-by: Lin Ming > --- > diff --git a/drivers/acpi/parser/psargs.c b/drivers/acpi/parser/psargs.c > index f1e8bf6..ef55d24 100644 > --- a/drivers/acpi/parser/psargs.c > +++ b/drivers/acpi/parser/psargs.c > @@ -268,7 +268,7 @@ acpi_ps_get_next_namepath(struct acpi_walk_state > *walk_state, > */ > if (ACPI_SUCCESS(status) && > possible_method_call && (node->type == ACPI_TYPE_METHOD)) { > - if (walk_state->op->common.aml_opcode == AML_UNLOAD_OP) { > + if (walk_state->op && walk_state->op->common.aml_opcode == > AML_UNLOAD_OP) { > /* > * acpi_ps_get_next_namestring has increased the AML pointer, > * so we need to restore the saved AML pointer for method call. Also, noticing your change, I can see why it makes no difference: Pekka already found that it is walk_state->op that has the value of 0xf7c12ec6 (e.g. the pointer being dereferenced), so the test will still succeed. On the other hand, I have discovered what seems to be a deficiency in kmemcheck (i.e. it might be my fault entirely), so it is possible that the warning is bogus. Will send an update shortly. Vegard -- "The animistic metaphor of the bug that maliciously sneaked in while the programmer was not looking is intellectually dishonest as it disguises that the error is the programmer's own creation." -- E. W. Dijkstra, EWD1036