From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751478AbaBBHJu (ORCPT ); Sun, 2 Feb 2014 02:09:50 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:35293 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751203AbaBBHJt (ORCPT ); Sun, 2 Feb 2014 02:09:49 -0500 Date: Sun, 2 Feb 2014 08:11:14 +0100 From: Greg KH To: Linus Torvalds Cc: Linux Driver Project , Andrew Morton , Linux Kernel Mailing List Subject: Re: [GIT PULL] Staging wireless driver for 3.14-rc1 Message-ID: <20140202071114.GA2195@kroah.com> References: <20140131143203.GA6560@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 01, 2014 at 10:43:11AM -0800, Linus Torvalds wrote: > On Fri, Jan 31, 2014 at 6:32 AM, Greg KH wrote: > > > > Here's a single staging driver for a wireless chipset that has shown up > > in the SteamBox hardware. It is merged separately from the "main" > > staging pull request to sync up with the wireless api changes that came > > in from the networking tree. > > It causes an interesting warning for me: > > drivers/staging/rtl8821ae/rtl8821ae/dm.c: In function > ‘rtl8821ae_dm_clear_txpower_tracking_state’: > drivers/staging/rtl8821ae/rtl8821ae/dm.c:487:31: warning: iteration 2u > invokes undefined behavior [-Waggressive-loop-optimizations] > rtldm->bb_swing_idx_ofdm[p] = rtldm->default_ofdm_index; > ^ > drivers/staging/rtl8821ae/rtl8821ae/dm.c:485:2: note: containing loop > for (p = RF90_PATH_A; p < MAX_RF_PATH; ++p) { > ^ > > and gcc is entirely correct: that loop iterates from 0 to 3, and does this: > > rtldm->bb_swing_idx_ofdm[p] = rtldm->default_ofdm_index; > > but the bb_swing_idx_ofdm[] array only has two members. So the last > two iterations will overwrite bb_swing_idx_ofdm_current and the first > entry in bb_swing_idx_ofdm_base[]. > > Now, the bug does seem to be benign: bb_swing_idx_ofdm_current isn't > actually ever *used* as far as I can tell, and the first entry of > bb_swing_idx_ofdm_base[] will have been written with that same > "rtldm->default_ofdm_index" value. > > But gcc is absolutely correct, and that driver needs fixing. > > I've pulled it and will let it be because it doesn't seem to be an > issue in practice, but please fix it. The obvious fix would seem to > change the size of "2" to be "MAX_RF_PATH", but I'll abstain from > doing those kinds of changes in the merge when it doesn't seem to > affect the build or functionality). Ok, thanks, someone's already sent me that patch to fix this up, I'll queue it up for the post-rc1 set of staging tree fixes. greg k-h