From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#36609: 27.0.50; Possible race-condition in threading implementation Date: Thu, 10 Jun 2021 18:04:55 +0300 Message-ID: <83y2bhbw14.fsf@gnu.org> References: <87muhks3b5.fsf@hochschule-trier.de> <87fsxv8182.fsf@dick> <83wnr7gdd8.fsf@gnu.org> <875yyqg66k.fsf@dick> <83k0n6hjym.fsf@gnu.org> <87wnr2lnsj.fsf@dick> <83h7i6cj3z.fsf@gnu.org> <87bl8e2aya.fsf@dick> <8335tpdcq9.fsf@gnu.org> <87y2bhepl2.fsf@dick> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="21399"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 36609@debbugs.gnu.org To: dick.r.chiang@gmail.com Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Thu Jun 10 17:06:10 2021 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1lrMG2-0005Lc-3C for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 10 Jun 2021 17:06:10 +0200 Original-Received: from localhost ([::1]:43116 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lrMG1-0000cZ-4K for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 10 Jun 2021 11:06:09 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:48300) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lrMFu-0000Zo-Gy for bug-gnu-emacs@gnu.org; Thu, 10 Jun 2021 11:06:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:54250) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lrMFu-0006lw-8w for bug-gnu-emacs@gnu.org; Thu, 10 Jun 2021 11:06:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1lrMFu-00010T-1w for bug-gnu-emacs@gnu.org; Thu, 10 Jun 2021 11:06:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 10 Jun 2021 15:06:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 36609 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: fixed Original-Received: via spool by 36609-submit@debbugs.gnu.org id=B36609.16233375283820 (code B ref 36609); Thu, 10 Jun 2021 15:06:02 +0000 Original-Received: (at 36609) by debbugs.gnu.org; 10 Jun 2021 15:05:28 +0000 Original-Received: from localhost ([127.0.0.1]:37561 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lrMFM-0000zY-3G for submit@debbugs.gnu.org; Thu, 10 Jun 2021 11:05:28 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:50278) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lrMFK-0000zL-3n for 36609@debbugs.gnu.org; Thu, 10 Jun 2021 11:05:26 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:54262) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lrMFE-0006Lj-Jr; Thu, 10 Jun 2021 11:05:20 -0400 Original-Received: from 84.94.185.95.cable.012.net.il ([84.94.185.95]:3120 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lrMF2-0001OZ-UR; Thu, 10 Jun 2021 11:05:11 -0400 In-Reply-To: <87y2bhepl2.fsf@dick> (dick.r.chiang@gmail.com) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:208326 Archived-At: > From: dick.r.chiang@gmail.com > Cc: 36609@debbugs.gnu.org > Date: Thu, 10 Jun 2021 10:55:53 -0400 > > > You cannot have, for example, half of the bits of the variable set by one thread > > and the other half by another thread. > > I dunno, this seems like a sophomoric, rose-colored view of variable sharing > without regard to caching, or really any generally accepted guarantees about > POSIX threads. Is it, really? > > So can you describe what you think happens in your scenario that the > > offending change that added threads_holding_glib_lock causes? > > Two threads see `threads_holding_glib_lock` is "0" and both attempt > acquiring the lock (line 43, xgselect.c) > > Or, two threads see `threads_holding_glib_lock` as "2" and glib > lock is never released. (line 37, xgselect.c) And you can show a GDB backtrace with values of the variable that supports that? And tell how that explains the hang that you see on the Lisp level? These are the details that I was asking from the first message you posted here.