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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 0C107C0044C for ; Sat, 3 Nov 2018 08:47:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D4AF72082D for ; Sat, 3 Nov 2018 08:47:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4AF72082D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727556AbeKCR6M (ORCPT ); Sat, 3 Nov 2018 13:58:12 -0400 Received: from mx2.suse.de ([195.135.220.15]:42214 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726316AbeKCR6M (ORCPT ); Sat, 3 Nov 2018 13:58:12 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 97523AE80; Sat, 3 Nov 2018 08:47:35 +0000 (UTC) Subject: Re: [PATCH] scsi: myrs: avoid stack overflow warning To: Arnd Bergmann , Hannes Reinecke , "James E.J. Bottomley" , "Martin K. Petersen" Cc: James Bottomley , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org References: <20181102154426.1951776-1-arnd@arndb.de> From: Hannes Reinecke Message-ID: Date: Sat, 3 Nov 2018 09:47:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181102154426.1951776-1-arnd@arndb.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/2/18 4:44 PM, Arnd Bergmann wrote: > Putting a 1024 byte data structure on the stack is generally a bad idea. > On 32-bit systems, it also triggers a compile-time warning when building > with -Og: > > drivers/scsi/myrs.c: In function 'myrs_get_ctlr_info': > drivers/scsi/myrs.c:212:1: error: the frame size of 1028 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] > > We only really need three members of the structure, so just read them > manually here instead of copying the entire structure. > > Fixes: 77266186397c ("scsi: myrs: Add Mylex RAID controller (SCSI interface)") > Signed-off-by: Arnd Bergmann > --- > drivers/scsi/myrs.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > > diff --git a/drivers/scsi/myrs.c b/drivers/scsi/myrs.c > index 0264a2e2bc19..b8d54ef8cf6d 100644 > --- a/drivers/scsi/myrs.c > +++ b/drivers/scsi/myrs.c > @@ -163,9 +163,12 @@ static unsigned char myrs_get_ctlr_info(struct myrs_hba *cs) > dma_addr_t ctlr_info_addr; > union myrs_sgl *sgl; > unsigned char status; > - struct myrs_ctlr_info old; > + unsigned short ldev_present, ldev_critical, ldev_offline; > + > + ldev_present = cs->ctlr_info->ldev_present; > + ldev_critical = cs->ctlr_info->ldev_critical; > + ldev_offline = cs->ctlr_info->ldev_offline; > > - memcpy(&old, cs->ctlr_info, sizeof(struct myrs_ctlr_info)); > ctlr_info_addr = dma_map_single(&cs->pdev->dev, cs->ctlr_info, > sizeof(struct myrs_ctlr_info), > DMA_FROM_DEVICE); > @@ -198,9 +201,9 @@ static unsigned char myrs_get_ctlr_info(struct myrs_hba *cs) > cs->ctlr_info->rbld_active + > cs->ctlr_info->exp_active != 0) > cs->needs_update = true; > - if (cs->ctlr_info->ldev_present != old.ldev_present || > - cs->ctlr_info->ldev_critical != old.ldev_critical || > - cs->ctlr_info->ldev_offline != old.ldev_offline) > + if (cs->ctlr_info->ldev_present != ldev_present || > + cs->ctlr_info->ldev_critical != ldev_critical || > + cs->ctlr_info->ldev_offline != ldev_offline) > shost_printk(KERN_INFO, cs->host, > "Logical drive count changes (%d/%d/%d)\n", > cs->ctlr_info->ldev_critical, > Reviewed-by: Hannes Reinecke Cheers, Hannes