From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Andreas Schwab Newsgroups: gmane.emacs.devel Subject: Re: scratch/sigchld-fd 8f0ce42 1/2: Fix deadlock when receiving SIGCHLD during 'pselect'. Date: Wed, 20 Jan 2021 16:48:43 +0100 Message-ID: <87sg6vvcbo.fsf@igel.home> References: <20210116184947.2105.45267@vcs0.savannah.gnu.org> <20210116184949.3C17C211A5@vcs0.savannah.gnu.org> <834kjd7yk5.fsf@gnu.org> <83turc7n93.fsf@gnu.org> <871regr6x5.fsf@igel.home> <83r1mg6zy2.fsf@gnu.org> <87pn20vwac.fsf@igel.home> <504E9D30-9AB0-4AF7-A128-66AB17983B67@gnu.org> <87lfcovuec.fsf@igel.home> <5638F98B-832B-456A-89F6-559DFB43BBAD@gnu.org> <87czxzx68b.fsf@igel.home> <83k0s77hhu.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="23738"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1.90 (gnu/linux) Cc: phst@google.com, p.stephani2@gmail.com, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Jan 20 16:50:03 2021 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1l2FkB-00065H-Hb for ged-emacs-devel@m.gmane-mx.org; Wed, 20 Jan 2021 16:50:03 +0100 Original-Received: from localhost ([::1]:39932 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l2FkA-0002tr-FJ for ged-emacs-devel@m.gmane-mx.org; Wed, 20 Jan 2021 10:50:02 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:51362) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l2Fj2-0001gn-DP for emacs-devel@gnu.org; Wed, 20 Jan 2021 10:48:52 -0500 Original-Received: from mail-out.m-online.net ([2001:a60:0:28:0:1:25:1]:57062) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l2Fiy-0000zM-AT; Wed, 20 Jan 2021 10:48:51 -0500 Original-Received: from frontend01.mail.m-online.net (unknown [192.168.8.182]) by mail-out.m-online.net (Postfix) with ESMTP id 4DLVLN6Rshz1rvBS; Wed, 20 Jan 2021 16:48:44 +0100 (CET) Original-Received: from localhost (dynscan1.mnet-online.de [192.168.6.70]) by mail.m-online.net (Postfix) with ESMTP id 4DLVLN62Xbz1r2xq; Wed, 20 Jan 2021 16:48:44 +0100 (CET) X-Virus-Scanned: amavisd-new at mnet-online.de Original-Received: from mail.mnet-online.de ([192.168.8.182]) by localhost (dynscan1.mail.m-online.net [192.168.6.70]) (amavisd-new, port 10024) with ESMTP id 0RpPLAYhMioK; Wed, 20 Jan 2021 16:48:44 +0100 (CET) X-Auth-Info: TaWuPnPgukLRInr6BUV9I+xRV/wKBL4n0VcLj8tdR+cHgn8FT+I8o/K4HZVVG1ry Original-Received: from igel.home (ppp-46-244-163-184.dynamic.mnet-online.de [46.244.163.184]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.mnet-online.de (Postfix) with ESMTPSA; Wed, 20 Jan 2021 16:48:44 +0100 (CET) Original-Received: by igel.home (Postfix, from userid 1000) id 809732C3624; Wed, 20 Jan 2021 16:48:43 +0100 (CET) X-Yow: I'm having a MID-WEEK CRISIS! In-Reply-To: <83k0s77hhu.fsf@gnu.org> (Eli Zaretskii's message of "Wed, 20 Jan 2021 17:30:53 +0200") Received-SPF: pass client-ip=2001:a60:0:28:0:1:25:1; envelope-from=whitebox@nefkom.net; helo=mail-out.m-online.net X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.248, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:263209 Archived-At: On Jan 20 2021, Eli Zaretskii wrote: > So maybe this is the problem we should solve: make the SIGCHLD handler > reset the bit of the process's output from the fd_set passed to > pselect. You cannot do that. That creates races all over the place. Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."