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#46256: [feature/native-comp] AOT eln files ignored if run from build tree Date: Tue, 09 Mar 2021 14:36:11 +0200 Message-ID: <83ft14qzb8.fsf@gnu.org> References: <83h7m84h9g.fsf@gnu.org> <86v9ao5czu.fsf@gmail.com> <86wnutogrh.fsf@gmail.com> <86wnut8fb9.fsf@gmail.com> <861rd1tbpa.fsf@gmail.com> <83pn0km6y3.fsf@gnu.org> <86ft1f8ara.fsf@gmail.com> <83sg5cjdn8.fsf@gnu.org> <83r1kwjcy2.fsf@gnu.org> <8335x6u9o4.fsf@gnu.org> <83zgzesrku.fsf@gnu.org> <83tupms4mp.fsf@gnu.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="38665"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 46256@debbugs.gnu.org, andrewjmoreton@gmail.com, akrl@sdf.org To: Pip Cet Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Tue Mar 09 13:46:12 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 1lJbkZ-0009xh-Hd for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 09 Mar 2021 13:46:11 +0100 Original-Received: from localhost ([::1]:60056 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lJbkY-0005Wn-En for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 09 Mar 2021 07:46:10 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:56818) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lJbbi-0007IW-I1 for bug-gnu-emacs@gnu.org; Tue, 09 Mar 2021 07:37:03 -0500 Original-Received: from debbugs.gnu.org ([209.51.188.43]:34336) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lJbbi-0004LX-AU for bug-gnu-emacs@gnu.org; Tue, 09 Mar 2021 07:37:02 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1lJbbi-0003Br-7q for bug-gnu-emacs@gnu.org; Tue, 09 Mar 2021 07:37:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Tue, 09 Mar 2021 12:37:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 46256 X-GNU-PR-Package: emacs Original-Received: via spool by 46256-submit@debbugs.gnu.org id=B46256.161529338912224 (code B ref 46256); Tue, 09 Mar 2021 12:37:02 +0000 Original-Received: (at 46256) by debbugs.gnu.org; 9 Mar 2021 12:36:29 +0000 Original-Received: from localhost ([127.0.0.1]:45882 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lJbbB-0003B6-0b for submit@debbugs.gnu.org; Tue, 09 Mar 2021 07:36:29 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:38792) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lJbb7-0003Aq-R3 for 46256@debbugs.gnu.org; Tue, 09 Mar 2021 07:36:28 -0500 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:36027) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lJbb0-0003pL-5x; Tue, 09 Mar 2021 07:36:18 -0500 Original-Received: from 84.94.185.95.cable.012.net.il ([84.94.185.95]:1766 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1lJbax-0002R1-6x; Tue, 09 Mar 2021 07:36:17 -0500 In-Reply-To: (message from Pip Cet on Mon, 8 Mar 2021 10:45:49 +0000) 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:201906 Archived-At: > From: Pip Cet > Date: Mon, 8 Mar 2021 10:45:49 +0000 > Cc: Eli Zaretskii , 46256@debbugs.gnu.org, andrewjmoreton@gmail.com > > > IIUC (and make sense to me) the issue is that we are leaving two pointer > > pointing to the same handle: One is in the CU_2 allocated by > > 'Fnative_elisp_load' and later discarded by 'load_comp_unit' when > > reloading the same filename. The other is the original CU_1 created the > > first time this filename was loaded. > > > > When CU_2 will be GC'ed because discarded we'll get the problem because > > we'll dlclose the handle. Is this correct? > > CU_1 is GC'ed first. CU_2, for whatever reason, isn't GC'ed in the same cycle. > > > In case isn't the attached curing the issue as well? > > I don't think so. The problem is that we have an invalid Lisp_Object > in the shared library, not that we're calling dlclose() too often.. > > Again, there's no real cost to fixing this: at best, we avoid a > catastrophic use-after-free. At worst, we nulled out a word of memory > only for it to be unmapped a moment later, no harm done. Once again, you are discussing a scenario whose relation to Real Life I'm not sure I understand. When will a cu be GC'ed? Isn't that when a .eln file is unloaded? And isn't it true that it can only be unloaded if the user or some code calls unload-feature or something similar? If the above is true, then the probability of this scenario to happen is very low, and in my particular case it is strictly zero. Not that I object to making the code robust in those rare cases, but we are discussing a particular crash. > > PS I couldn't reproduce using the lisp reproducer both on my 64bit both > > on my 32bit system (I left it looping for a while), is that reproducer > > working for you? > > Have you modified dynlib_open() to leak the shared object? That's what > I think might be happening for Eli What shared object is supposed to leak in my case, and why?