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 [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 9147739217AB for ; Wed, 7 Dec 2022 10:01:35 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 9147739217AB Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670407294; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=7g99yohsYCWo8gNOITVcVLA80vzE2sMltwBv1JP5aIs=; b=LZXs/xqojeeXS/hdlU9S8eVgdckV3TuNJoVsZOMMKfJlBUubUtK12FmAhtnT3t/a9xa7lc v9AaK7AxnSYbVuVs/GkDrky0OjLCHu9/vTvO9VGJx9pPbPnYvA095V+O4np5XdF/0xftYn fVtZcI470rhM0WXpQ/7T+krRDwkKCWU= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-49-CyoGEZ7POvOXWaHIQqWsVA-1; Wed, 07 Dec 2022 05:01:28 -0500 X-MC-Unique: CyoGEZ7POvOXWaHIQqWsVA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5AF3E1C05B0A; Wed, 7 Dec 2022 10:01:28 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.2.16.63]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1985A1415100; Wed, 7 Dec 2022 10:01:26 +0000 (UTC) From: Florian Weimer To: Siddhesh Poyarekar Cc: Zack Weinberg via Libc-alpha , Zack Weinberg , DJ Delorie Subject: Re: [RFC] Supporting malloc_usable_size References: <20221124213258.305192-1-siddhesh@gotplt.org> <87sfhyrp19.fsf@igel.home> <87o7smrnlh.fsf@igel.home> <87pmd2rnce.fsf@oldenburg.str.redhat.com> <5758633c-9989-e463-0eb6-33f483439289@owlfolio.org> <87359tpp1m.fsf@oldenburg.str.redhat.com> Date: Wed, 07 Dec 2022 11:01:23 +0100 In-Reply-To: (Siddhesh Poyarekar's message of "Tue, 6 Dec 2022 14:25:53 -0500") Message-ID: <874ju7ilcc.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 3.1 on 10.11.54.7 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-5.0 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_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: * Siddhesh Poyarekar: > On 2022-12-05 15:35, Florian Weimer via Libc-alpha wrote: >> I think it's a backwards-incompatible change. The existing manual page >> documents the function as MT-Safe. >> With this new policy, I don't think malloc_usable_size is useful for >> anything at all, and we can just deprecate it (with a deprecation >> warning message) and eventually remove it from linking (after >> considering the impact on replacement malloc implementations, but I >> don't think it will be problematic). > > We don't have consensus on deprecation unfortunately. DJ is of the > opinion that the limited use (knowing the usable size but not being > able to do anything with it) may be useful enough for some programs. > With that position, making it clear that the extra space is never > safely usable and then just leaving it at that is probably the least > worst out. Maybe we could add a deprecation warning just for -D_FORTIFY_SOURCE=3? DJ, what do you think? Thanks, Florian