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 945453858D3C for ; Mon, 22 Aug 2022 18:22:02 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 945453858D3C 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-437-Ia2tXqaOO-64d-iFyZT7-A-1; Mon, 22 Aug 2022 14:21:59 -0400 X-MC-Unique: Ia2tXqaOO-64d-iFyZT7-A-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C695285A585; Mon, 22 Aug 2022 18:21:58 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.192.199]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 282002026D4C; Mon, 22 Aug 2022 18:21:58 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella Netto via Libc-help Cc: Rain , Adhemerval Zanella Netto Subject: Re: posix_spawn: parent can get stuck in uninterruptible sleep if child receives SIGTSTP early enough References: <2921668c-773e-465d-9480-0abb6f979bf9@www.fastmail.com> <7727e4de-a8da-1e6b-4d7c-68a132750996@linaro.org> <64917a2f-788b-4695-b799-63bbb8a4873f@www.fastmail.com> Date: Mon, 22 Aug 2022 20:21:56 +0200 In-Reply-To: (Adhemerval Zanella Netto via Libc-help's message of "Mon, 22 Aug 2022 14:48:59 -0300") Message-ID: <87tu64w33v.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 2.78 on 10.11.54.4 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_LOW, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-help@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-help mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Aug 2022 18:22:04 -0000 * Adhemerval Zanella Netto via Libc-help: > Right, my mistake. I understood the issue better now, although I am > still puzzled why SIGTSTP is only being triggered on sigprocmask (sing > default action is still to stop PROCESS). I think it's a maskable stop, not an unmaskable one, like SIGSTOP. This looks a vfork-specific bug that can't happen with fork. I don't see how to fix it in a generic fashion because we can't unblock SIGTSTP and launch the new process in an atomic fashion. Thanks, Florian