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 A01DB3847806 for ; Tue, 25 May 2021 07:43:03 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org A01DB3847806 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-421-8tvA417nOSGtf_hdR93q6g-1; Tue, 25 May 2021 03:43:01 -0400 X-MC-Unique: 8tvA417nOSGtf_hdR93q6g-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 595D9801106; Tue, 25 May 2021 07:43:00 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-113-228.ams2.redhat.com [10.36.113.228]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7363370136; Tue, 25 May 2021 07:42:59 +0000 (UTC) From: Florian Weimer To: Bruno Haible Cc: libc-alpha@sourceware.org Subject: Re: [PATCH 3/3] Misc: Add and the cstack_* family of functions References: <73724441.XAIsEQcG03@omega> <2323426.9O4c1bNasL@omega> Date: Tue, 25 May 2021 09:42:57 +0200 In-Reply-To: <2323426.9O4c1bNasL@omega> (Bruno Haible's message of "Mon, 24 May 2021 17:28:23 +0200") Message-ID: <87pmxf1cou.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 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.7 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_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: Tue, 25 May 2021 07:43:04 -0000 * Bruno Haible: >> * The ability to have a guard page at the stack bottom. > > Your documentation explains why this is useful: > > This guard region can sometimes catch stack-based buffer > overflows and turn them into a segmentation fault. > > It would be useful to have this feature on the thread stacks, in the > first place. That is, add some pthread_attr_setbottomguard() function > to that allows the application to enable this for the > thread stacks. This feature is already enabled by default. See pthread_attr_setguardsize. What we do not have is a way to set an alternate signal stack upon thread creation that is also automatically deallocated once the thread exits. I planned to propose this as an additional interface afterwards. Thanks, Florian