From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758532Ab2CBJAM (ORCPT ); Fri, 2 Mar 2012 04:00:12 -0500 Received: from mx01.sz.bfs.de ([194.94.69.103]:15825 "EHLO mx01.sz.bfs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757412Ab2CBJAK (ORCPT ); Fri, 2 Mar 2012 04:00:10 -0500 Message-ID: <4F508C16.30900@bfs.de> Date: Fri, 02 Mar 2012 10:00:06 +0100 From: walter harms Reply-To: wharms@bfs.de User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; de; rv:1.9.1.16) Gecko/20101125 SUSE/3.0.11 Thunderbird/3.0.11 MIME-Version: 1.0 To: Dan Carpenter CC: Eric Wollesen , Doug Thompson , list-edac@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [patch] edac i5000: fix pointer math in i5000_get_mc_regs() References: <20120302065441.GB24508@elgon.mountain> In-Reply-To: <20120302065441.GB24508@elgon.mountain> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 02.03.2012 07:54, schrieb Dan Carpenter: > "pvt->ambase" is a u64 datatype. The intent here is to fill the first > half in the first call to pci_read_config_dword() and the other half in > the second. Unfortunately the pointer math is wrong so we set the wrong > data. > > Signed-off-by: Dan Carpenter > --- > I don't have the hardware to test this. Please review carefully. > > diff --git a/drivers/edac/i5000_edac.c b/drivers/edac/i5000_edac.c > index 4dc3ac2..fcdc4ab 100644 > --- a/drivers/edac/i5000_edac.c > +++ b/drivers/edac/i5000_edac.c > @@ -1130,7 +1130,7 @@ static void i5000_get_mc_regs(struct mem_ctl_info *mci) > pci_read_config_dword(pvt->system_address, AMBASE, > (u32 *) & pvt->ambase); > pci_read_config_dword(pvt->system_address, AMBASE + sizeof(u32), > - ((u32 *) & pvt->ambase) + sizeof(u32)); > + (u32 *)((char *) &pvt->ambase + sizeof(u32))); > > maxdimmperch = pvt->maxdimmperch; > maxch = pvt->maxch; i think this is hard to understand. personally i would prefer a union or other more obvious solutions. my suggestion would be to get rid of this. u32 bottom,top; pci_read_config_dword(pvt->system_address, AMBASE, &bottom); pci_read_config_dword(pvt->system_address, AMBASE+ sizeof(u32), &top); maxdimmperch=(u64)top<<32|bottom; you can find this pattern in other parts of the kernel also. hope that helps re, wh