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 ABE9C3858D1E for ; Fri, 8 Sep 2023 12:35:12 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org ABE9C3858D1E 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=1694176512; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xbe5KYh2g8SCsq+2YmKPBHXjv6oOje3dmp+Ew6E/Ong=; b=UwpfDN4o2Fe985auCre0RRrtYHwhU0CGNCuqzZ+vzXx3OMEcrUKXzHOzWPOVfjJbApiJcM oCTYey3udI0gxVMfLvTAJfUBSnQ67POIi0LgzUlmLWeq2e6EWH9sXucAE3mjHycb2b9+nm 09PSY1MEumoiFQ08Fp596Tm0j2QQct4= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-73-cPM2Ek2lNGS4BksozYfLGw-1; Fri, 08 Sep 2023 08:35:10 -0400 X-MC-Unique: cPM2Ek2lNGS4BksozYfLGw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 91F77101CA83; Fri, 8 Sep 2023 12:35:10 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.2.16.33]) by smtp.corp.redhat.com (Postfix) with ESMTPS id ECD1E2026D2B; Fri, 8 Sep 2023 12:35:09 +0000 (UTC) From: Florian Weimer To: Carlos O'Donell Cc: Carlos O'Donell via Libc-alpha , Adhemerval Zanella Subject: Re: [PATCH v7] nptl: Fix Race conditions in pthread cancellation [BZ#12683] References: <20230524135126.3174670-1-adhemerval.zanella@linaro.org> <87fs3zawud.fsf@oldenburg.str.redhat.com> Date: Fri, 08 Sep 2023 14:35:08 +0200 In-Reply-To: (Carlos O'Donell's message of "Fri, 8 Sep 2023 08:22:04 -0400") Message-ID: <875y4k7shv.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-4.6 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_H4,RCVD_IN_MSPIKE_WL,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: * Carlos O'Donell: > In Adhemerval's v7 implementation the i686 and ia64 ports loose vDSO > support for cancellable syscalls. That is a regression for existing > ports? > > The more technical question is: Will vDSO functions intersect the set > of functions for which we have cancellation points today? I think Adhemerval drops use of the kernel-provided userspace entry point (switching to =E2=80=9Cint $0x80=E2=80=9D on i386 instead). That ent= ry point is in the vDSO, and its address is communicated by the kernel via AT_SYSINFO in the auxiliary vector, or as e_entry for the vDSO. This is not not a vDSO call in the traditional sense, as say for clock_gettime. So I think this is okay. It's a consideration for further ports because the e_entry mechanism won't work for them. But for *those* ports, we can work on fixing the performance implications of not using e_entry. Doing so for i386 and ia64 isn't realistic, in my opinion. Thanks, Florian