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 908BB394BE2C for ; Tue, 1 Jun 2021 08:40:09 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 908BB394BE2C 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-390-AKT6j5XDNnypHa7XAjbx1Q-1; Tue, 01 Jun 2021 04:38:53 -0400 X-MC-Unique: AKT6j5XDNnypHa7XAjbx1Q-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 39511BBEEE; Tue, 1 Jun 2021 08:38:52 +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 C658269FB2; Tue, 1 Jun 2021 08:38:47 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella via Libc-alpha Subject: Re: [PATCH v2 3/9] nptl: Install cancellation handler on pthread_cancel References: <20210527172823.3461314-1-adhemerval.zanella@linaro.org> <20210527172823.3461314-4-adhemerval.zanella@linaro.org> Date: Tue, 01 Jun 2021 10:38:45 +0200 In-Reply-To: (Adhemerval Zanella via Libc-alpha's message of "Mon, 31 May 2021 15:18:15 -0300") Message-ID: <87k0ne6ktm.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 10.5.11.11 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, 01 Jun 2021 08:40:11 -0000 * Adhemerval Zanella via Libc-alpha: > On 27/05/2021 14:28, Adhemerval Zanella wrote: >> Now that cancellation is not used anymore to handle thread setup >> creation failure, the sighandle can be installed only when >> pthread_cancel is actually used. >> >> Checked on x86_64-linux-gnu and aarch64-linux-gnu. > > I also think it fixes BZ#14744, the cancellation handler is now used > solely when pthread_cancel is actually issue. The sigcancel_handler > already prevents signals from other processes and cancellation from > other processes are an extension that I think it does not really > make sense (as Carlos has pointed ack on the bug report). I'm not sure if bug 14744 actually exists, given the checks we have in the cancellation signal handler. Particularly the si_pid check should block acting on signals sent from another process. And locally, we filter out the NPTL signals in the system call wrapppers (and we consider direct system calls undefined in this context). Thanks, Florian