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.devel Subject: Re: MPS: profiler Date: Fri, 21 Jun 2024 13:56:37 +0300 Message-ID: <86le2ylg2i.fsf@gnu.org> References: <87v823xvq1.fsf@localhost> <86cyobmmhc.fsf@gnu.org> <87r0crxung.fsf@localhost> <87le2zxsqx.fsf@localhost> <6l0QgWrRSaN5-vKBUqAO1SaW-DUtxBNNSqU_w98pQy-u7eFL8hnuX7PbY3RKDMSoQWALFCSqS4w0K5gowCsHZju_ODw6UbRYjZEVONLvqcc=@protonmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="632"; mail-complaints-to="usenet@ciao.gmane.io" Cc: yantar92@posteo.net, gerd.moellmann@gmail.com, emacs-devel@gnu.org, eller.helmut@gmail.com To: Pip Cet Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Fri Jun 21 12:57:09 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 1sKbx5-000AJl-Po for ged-emacs-devel@m.gmane-mx.org; Fri, 21 Jun 2024 12:57:07 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sKbwh-0002KS-Eq; Fri, 21 Jun 2024 06:56:43 -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 1sKbwf-0002I3-FQ for emacs-devel@gnu.org; Fri, 21 Jun 2024 06:56:41 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sKbwf-0006N8-5h; Fri, 21 Jun 2024 06:56:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-version:References:Subject:In-Reply-To:To:From: Date; bh=ZS8EQtPcUL0YLFERfF3Ie/1MERPY7+R3z479sHTmmMY=; b=YbPE6GYP/3b7BZ5Vmq46 39O7vf2UWNZ7upqCwsix0KMbKJLQJdVp3o8bfetTjWXp3N0BYzr0YeecNS5KmFX1/Uy6YjHbBROke rpThofr6ll1zBHD6gECUHrILSxgHZpq/UGLEtezMOLjDHkPo+jfIbViveIVcQewXIYlG62Fhw+zFa CqUrzc+LopXjWvwiEkJ2/ohw6zq2hUwrexLf04XqAR19ngPPzb6Ywrqgmby7PifwumtYZDXqOUbeX 1eSwomcTGPABot4x3ZMJExrAj2jaTCM0kYmGnmcAoS1WKnvp9EvohtB14/KJBqaGslnVQTVW8nD8v DIPgHiYxnbHO1g==; In-Reply-To: <6l0QgWrRSaN5-vKBUqAO1SaW-DUtxBNNSqU_w98pQy-u7eFL8hnuX7PbY3RKDMSoQWALFCSqS4w0K5gowCsHZju_ODw6UbRYjZEVONLvqcc=@protonmail.com> (message from Pip Cet on Fri, 21 Jun 2024 10:49:41 +0000) 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:320385 Archived-At: > Date: Fri, 21 Jun 2024 10:49:41 +0000 > From: Pip Cet > Cc: Gerd Möllmann , Eli Zaretskii , emacs-devel@gnu.org, eller.helmut@gmail.com > > So, yes, what I described is precisely what we're seeing in the backtrace. No, you were describing a nested protection-related SIGSEGV. But we haven't yet established that the second SIGSEGV is due to protection. I asked Ihor to show the data in the function that segfaults, but he didn't do that yet. Only after we see the data, we can decide that this is a nested protection-related SIGSEGV, not a segfault caused by our code accessing data that is no longer there. In general, I'd expect MPS to be ready for the case where this kind of combination of signals happens. At the very least, this is needed for supporting -gprof, but also for other legitimate techniques. It is, of course, possible that MPS has a bug in that area, or even some design flaw or limitation (in the latter case, it's supposed to be documented somewhere, btw), but I'd first assume it's our bug, not theirs, and explore that possibility first.