From patchwork Mon May 18 17:37:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 225656 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=unavailable 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 E2FEFC433E1 for ; Mon, 18 May 2020 18:17:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B302020671 for ; Mon, 18 May 2020 18:17:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589825830; bh=wJ83Aa/krfODHRG3CrpUcfs0wKQF3Hb1hqV/wfhwlF8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dPyGJnpHTQRfqzaZQZuBPqAzc+XhWwSn0HZiAuKDtcmiOGwYRZxjy0W8YvcsahAaZ 82qnN9oROiepDZ5j1MwxJQLdFdt0PvzWkX/D1bgpnfB47OV9iTsyOk3D7VcJ+ON27i gQ+0oHCzm/ElGqecSSAbX0q+TewzCE0vCnsWyygI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730836AbgERSRG (ORCPT ); Mon, 18 May 2020 14:17:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:36236 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731805AbgERR5d (ORCPT ); Mon, 18 May 2020 13:57:33 -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 08C81207C4; Mon, 18 May 2020 17:57:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589824652; bh=wJ83Aa/krfODHRG3CrpUcfs0wKQF3Hb1hqV/wfhwlF8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f1WIQbnw6S9EQSjdzKHJYbzUJ8V1osQNA7Tvj3nyr5agjBPekic8L/ZuAVGzIGB6U 1dPNgamgx0oX5iSUBV+QBIimNhrOQsl2mmraBxkByvjL3aMmB0AGNUU7lr5xFipOyE KbEQCY3SzxWFalQJrOz3e3jE1i322RN3IzWbZT10= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Linus Torvalds Subject: [PATCH 5.4 097/147] gcc-10: disable array-bounds warning for now Date: Mon, 18 May 2020 19:37:00 +0200 Message-Id: <20200518173525.578271833@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200518173513.009514388@linuxfoundation.org> References: <20200518173513.009514388@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 @@ -858,6 +858,7 @@ 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)