From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id DDB743858D39 for ; Fri, 9 Jul 2021 06:35:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org DDB743858D39 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-419-sDZxEBoBM_CBcVfPS0RdmA-1; Fri, 09 Jul 2021 02:35:07 -0400 X-MC-Unique: sDZxEBoBM_CBcVfPS0RdmA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 12D3D802929; Fri, 9 Jul 2021 06:35:06 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-112-103.rdu2.redhat.com [10.10.112.103]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 396E95C1A3; Fri, 9 Jul 2021 06:35:05 +0000 (UTC) From: Florian Weimer To: Martin Sebor via Libc-alpha Subject: Re: [RFC patch] avoid warning on accesses to hardwired address References: <59b05c40-d0a8-233a-27c5-104b24bdc9b4@gmail.com> Date: Fri, 09 Jul 2021 08:34:56 +0200 In-Reply-To: <59b05c40-d0a8-233a-27c5-104b24bdc9b4@gmail.com> (Martin Sebor via Libc-alpha's message of "Thu, 8 Jul 2021 18:55:26 -0600") Message-ID: <87sg0oj8q7.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Jul 2021 06:35:09 -0000 * Martin Sebor via Libc-alpha: > Thanks to recent code refactoring in GCC 12, -Warray-bounds has > started to diagnose accesses to constant addresses just like many > other flow based warnings do (e.g., -Wstringop-overflow). > The warnings are meant to help detect accesses resulting from > invalid arithmetic on null pointers. There may be a better way > to detect them but GCC doesn't have the detection yet. This > warning change has in turn exposed Glibc's uses of this trick > in the implementation of the THREAD_SELF macro. The warning needs to be disabled in GCC for named address spaces. Null pointers are not special for them. Thanks, Florian