From patchwork Mon May 18 17:36:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 225575 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=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 80494C433DF for ; Mon, 18 May 2020 18:26:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 552E52065F for ; Mon, 18 May 2020 18:26:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589826410; bh=dfVQR4veVC0esrH3yIaUeif+5yaaxqOggWhhT+OkLVE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=wlBTLnFO8o8V9FBbJKaiKT3GOaeGX4AXBXs6XmB1SvIhzb92YEGyiLMLXDRf5Cmhl Gt+BTgZeA2QduoCKLxulVlgmaCX/B5hB1MSjmbOZhMNI9/WUFLTA2x9A85TNj1llcp MZ5Yjq4HiXqYY/IZ6k2EutFXnv9rkCAFEKX3sZoE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729804AbgERS0t (ORCPT ); Mon, 18 May 2020 14:26:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:43682 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729847AbgERRpD (ORCPT ); Mon, 18 May 2020 13:45:03 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 592B620715; Mon, 18 May 2020 17:45:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589823902; bh=dfVQR4veVC0esrH3yIaUeif+5yaaxqOggWhhT+OkLVE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nrpqngwMb10LhYtSce77MpW1M/KK10zC8Vqi5o9Ny0AtmLjA3t7gbKiGo+EdDr1GE MRcOeBjeUavqHnvuMi8OY4NywlUIHV+ynkSB0RmeHWDU6jArTVEsjhmsdEeIf55JDO wcPVCt10OcUhFlE2Je5olCbkDzykV1t76ha9IjxA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Linus Torvalds Subject: [PATCH 4.9 65/90] gcc-10: disable array-bounds warning for now Date: Mon, 18 May 2020 19:36:43 +0200 Message-Id: <20200518173504.341089242@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200518173450.930655662@linuxfoundation.org> References: <20200518173450.930655662@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Linus Torvalds commit 44720996e2d79e47d508b0abe99b931a726a3197 upstream. This is another fine warning, related to the 'zero-length-bounds' one, but hitting the same historical code in the kernel. Because C didn't historically support flexible array members, we have code that instead uses a one-sized array, the same way we have cases of zero-sized arrays. The one-sized arrays come from either not wanting to use the gcc zero-sized array extension, or from a slight convenience-feature, where particularly for strings, the size of the structure now includes the allocation for the final NUL character. So with a "char name[1];" at the end of a structure, you can do things like v = my_malloc(sizeof(struct vendor) + strlen(name)); and avoid the "+1" for the terminator. Yes, the modern way to do that is with a flexible array, and using 'offsetof()' instead of 'sizeof()', and adding the "+1" by hand. That also technically gets the size "more correct" in that it avoids any alignment (and thus padding) issues, but this is another long-term cleanup thing that will not happen for 5.7. So disable the warning for now, even though it's potentially quite useful. Having a slew of warnings that then hide more urgent new issues is not an improvement. Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- Makefile | 1 + 1 file changed, 1 insertion(+) --- a/Makefile +++ b/Makefile @@ -799,6 +799,7 @@ KBUILD_CFLAGS += $(call cc-disable-warni # We'll want to enable this eventually, but it's not going away for 5.7 at least KBUILD_CFLAGS += $(call cc-disable-warning, zero-length-bounds) +KBUILD_CFLAGS += $(call cc-disable-warning, array-bounds) # Enabled with W=2, disabled by default as noisy KBUILD_CFLAGS += $(call cc-disable-warning, maybe-uninitialized)