From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 286EFC433ED for ; Tue, 27 Apr 2021 09:32:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E0421613BC for ; Tue, 27 Apr 2021 09:32:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230316AbhD0JdR (ORCPT ); Tue, 27 Apr 2021 05:33:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:38760 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231148AbhD0JdP (ORCPT ); Tue, 27 Apr 2021 05:33:15 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BEE45613C2; Tue, 27 Apr 2021 09:32:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1619515952; bh=tPt28XM8aJLIshA3dm6rMjVcvA0FXwOFYDhvj9Mdv+Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=brhLK1kI4KhPfwhvrqbMh144h8bMt77mjN21VMVEqLk3g/oEwPlIB4TaswAg+4ULs cN2fYd18Fy6GadECxf8XbfGdmdQtynBAl1SIsf6+jKHFlzlfR8MyYbJjDbhs53f35Q tPoq7wh/bXDFMfqAORHoX7q2uvgbX5/vuVIzaWG4= Date: Tue, 27 Apr 2021 11:32:29 +0200 From: Greg Kroah-Hartman To: Arnd Bergmann Cc: Dan Carpenter , Arnd Bergmann , Fabio Aiuto , Ross Schmidt , Marco Cesati , Johannes Berg , Ivan Safonov , linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [v2] staging: rtl8723bs: avoid bogus gcc warning Message-ID: References: <20210422152648.2891996-1-arnd@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210422152648.2891996-1-arnd@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 22, 2021 at 05:26:19PM +0200, Arnd Bergmann wrote: > From: Arnd Bergmann > > gcc gets confused by some of the type casts and produces an > apparently senseless warning about an out-of-bound memcpy to > an unrelated array in the same structure: > > drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c: In function 'rtw_cfg80211_ap_set_encryption': > cc1: error: writing 8 bytes into a region of size 0 [-Werror=stringop-overflow=] > In file included from drivers/staging/rtl8723bs/include/drv_types.h:32, > from drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c:10: > drivers/staging/rtl8723bs/include/rtw_security.h:98:15: note: at offset [184, 4264] into destination object 'dot11AuthAlgrthm' of size 4 > 98 | u32 dot11AuthAlgrthm; /* 802.11 auth, could be open, shared, 8021x and authswitch */ > | ^~~~~~~~~~~~~~~~ > cc1: error: writing 8 bytes into a region of size 0 [-Werror=stringop-overflow=] > drivers/staging/rtl8723bs/include/rtw_security.h:98:15: note: at offset [264, 4344] into destination object 'dot11AuthAlgrthm' of size 4 > > This is a known gcc bug, and the patch here is only a workaround, > but the approach of using a temporary variable to hold a pointer > to the key also improves readability in addition to avoiding the > warning, so overall this should still help. What version of gcc causes this? Should this go into 5.13-final and be backported? Or is this only showing up on "unreleased" versions of gcc and it is safe to wait until 5.14? thanks, greg k-h