From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Ihor Radchenko Newsgroups: gmane.emacs.devel Subject: Re: MPS: a random backtrace while toying with gdb Date: Mon, 01 Jul 2024 17:17:06 +0000 Message-ID: <87msn18225.fsf@localhost> References: <87bk3jh8bt.fsf@localhost> <87wmm6rcv1.fsf@gmail.com> <86le2mhhsj.fsf@gnu.org> <875xtqramd.fsf@gmail.com> <86cynyhfsn.fsf@gnu.org> <87v81qp91g.fsf@gmail.com> <86tthafbix.fsf@gnu.org> <87plry6sv3.fsf@localhost> <86le2lfjqv.fsf@gnu.org> <87jzi5ibbe.fsf@localhost> <864j99fg0a.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="25177"; mail-complaints-to="usenet@ciao.gmane.io" Cc: eller.helmut@gmail.com, gerd.moellmann@gmail.com, pipcet@protonmail.com, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon Jul 01 19:16:39 2024 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 1sOKdq-0006KS-9M for ged-emacs-devel@m.gmane-mx.org; Mon, 01 Jul 2024 19:16:38 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sOKd3-0006Gv-BL; Mon, 01 Jul 2024 13:15:50 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sOKcv-0006Eq-4u for emacs-devel@gnu.org; Mon, 01 Jul 2024 13:15:43 -0400 Original-Received: from mout01.posteo.de ([185.67.36.65]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sOKcn-0001ro-9x for emacs-devel@gnu.org; Mon, 01 Jul 2024 13:15:40 -0400 Original-Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id D9964240029 for ; Mon, 1 Jul 2024 19:15:29 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1719854129; bh=ryb5Q7oW6obwLSuBiQl1qqo8qg4CVNp3hWQPjEr3c34=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type: From; b=iiWUzHUOj0Y8xICuCajS5uMyoMPcgZyqfjEj0ga05sj2B+8y3ajokzt75AMcLGPbq hLitAyb5V2+KZF3XlXacJQHeWBvnns56H9q7sg+GgyVvowtcXR0oLPhcUjyP2zWNfz Pnadaps4+1y0ppCx5hpyKTT++h+Ix6ajE1S8vrSZVUL9qHWT5nn2m6/Z91E4o0hjib fqi3cVM79lQBhScOh4FD2RXt8VxcyNbPdrMegguet3yjncv18w+JHUlZA7NIuoKQIH +4jAXC0P06l+hZY8ryE4PsyVbm97RPllg0z6PwG2talEfIGAc7S0qror8GIn7wNCSO M+0q500Ekr2GQ== Original-Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4WCXjs0Pjrz9rxB; Mon, 1 Jul 2024 19:15:28 +0200 (CEST) In-Reply-To: <864j99fg0a.fsf@gnu.org> Received-SPF: pass client-ip=185.67.36.65; envelope-from=yantar92@posteo.net; helo=mout01.posteo.de X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:321038 Archived-At: Eli Zaretskii writes: > As you can see, it all started when we called Fcons, to produce a cons > cell. That called igc_make_cons, which eventually called MPS > memory-allocation stuff (starting from frame #29). MPS called us back > (frame #21), and while in fix_lisp_obj, we got delivered SIGPROF, and > attempted to access some memory that was evidently behind the barrier. > The rest is history, because MPS kicked in and tried to take the arena > lock the second time. > > There's no other thread anywhere in sight here, this all happens in > the context of our own main (a.k.a. "Lisp") thread. I see. So, it is the other way around than what I thought. I looked a bit into mps sources and what I observe is mps_ap_fill -> ArenaEnter -> ArenaEnterLock -> LockClaim. This is active for the duration of our dflt_scan. Nothing can access the MPS arena and when something tries to, we get assertion failure. It looks like we can test whether the Arena is locked via /* mps_arena_busy -- is the arena part way through an operation? */ mps_bool_t mps_arena_busy(mps_arena_t arena) Although it does not help with the underlying problem with signal arriving while we are in the process of allocating a new object in the pool. I am wondering what happens in the same situation when using normal malloc. (Or may it never happen when using normal malloc?) -- Ihor Radchenko // yantar92, Org mode contributor, Learn more about Org mode at . Support Org development at , or support my work at