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 [63.128.21.124]) by sourceware.org (Postfix) with ESMTP id 0ABB63870889 for ; Wed, 4 Nov 2020 09:56:33 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 0ABB63870889 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-30-Gio6LRrsN829Gsn4Y3AdNQ-1; Wed, 04 Nov 2020 04:56:31 -0500 X-MC-Unique: Gio6LRrsN829Gsn4Y3AdNQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EDF868015A3; Wed, 4 Nov 2020 09:56:29 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-113-12.ams2.redhat.com [10.36.113.12]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BC2B561177; Wed, 4 Nov 2020 09:56:28 +0000 (UTC) From: Florian Weimer To: Siddhesh Poyarekar Cc: Jakub Jelinek , libc-alpha@sourceware.org, sguelton@redhat.com Subject: Re: [PATCH] Remove __warn_memset_zero_len [bz #25399] References: <20201104090547.1376086-1-siddhesh@sourceware.org> <87o8kd4gyq.fsf@oldenburg2.str.redhat.com> <20201104093619.GR3788@tucnak> <87d00t4fze.fsf@oldenburg2.str.redhat.com> Date: Wed, 04 Nov 2020 10:56:27 +0100 In-Reply-To: (Siddhesh Poyarekar's message of "Wed, 4 Nov 2020 15:22:37 +0530") Message-ID: <878sbh4f90.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.2 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H5, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) 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: Wed, 04 Nov 2020 09:56:34 -0000 * Siddhesh Poyarekar: > On 11/4/20 3:10 PM, Florian Weimer via Libc-alpha wrote: >> * Jakub Jelinek: >> >>> It is ok if it doesn't warn anymore, and it is ok if it is not in the >>> headers anymore, but one can still have object files or *.a libraries >>> compiled with gcc 4.9 and earlier against older glibc and that will >>> now fail to link altogether. >> In general, that is not supported. We have recently made an >> exception >> for __xstat. But in this case, linking after removal will only fail if >> there was an annoying linker warning before, so I think it's going to be >> very rare that this makes a difference. > > I suppose another way to look at this is that the patch does not fix > the link failure, it only ensures that the symbol doesn't appear in > the future by accident. > > We can then look at fixing the link failure by adding the symbol in if > someone actually cares enough to file another bug. Does that sound > reasonable? Eh, right. The __warn_memset_zero_len symbol is currently not part of libc_nonshared.a. (Our downstream build of 2.17 still has it, but the one based on 2.28 does not, due to a different GCC version being used.) So there is no new backwards compatibility impact from remove the __warndecl stuff. Thanks, Florian -- Red Hat GmbH, https://de.redhat.com/ , Registered seat: Grasbrunn, Commercial register: Amtsgericht Muenchen, HRB 153243, Managing Directors: Charles Cachera, Brian Klemm, Laurie Krebs, Michael O'Neill