From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Lars Ingebrigtsen Newsgroups: gmane.emacs.bugs Subject: bug#36649: 27.0.50; pure space and pdumper Date: Sun, 16 May 2021 15:38:26 +0200 Message-ID: <87a6oupzn1.fsf@gnus.org> References: <87sg5bt1bp.fsf@gmail.com> <4c1248b8-88cc-ca06-6bc8-9f0bb9a98c98@cs.ucla.edu> <87mtt0hupl.fsf@gnus.org> <83mtt02dyz.fsf@gnu.org> <877dk3hoko.fsf@gnus.org> <87y2cjg9mu.fsf@gnus.org> <83a6oz3lpm.fsf@gnu.org> <87lf8jg8o2.fsf@gnus.org> <838s4j3l2e.fsf@gnu.org> <87h7j7g7ft.fsf@gnus.org> <878s4jg67i.fsf@gnus.org> <834kf73iim.fsf@gnu.org> <874kf7g54z.fsf@gnus.org> <8335ur3hu8.fsf@gnu.org> <83a6oy20bj.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="5575"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: eggert@cs.ucla.edu, rpluim@gmail.com, stefan@marxist.se, schwab@linux-m68k.org, monnier@iro.umontreal.ca, pipcet@gmail.com, 36649@debbugs.gnu.org, akrl@sdf.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sun May 16 15:39:25 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 1liGzM-0001GP-SU for geb-bug-gnu-emacs@m.gmane-mx.org; 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Original-Received: from cm-84.212.220.105.getinternet.no ([84.212.220.105] helo=xo) by quimby.gnus.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1liGyR-0007Nk-NY; Sun, 16 May 2021 15:38:30 +0200 Face: iVBORw0KGgoAAAANSUhEUgAAADAAAAAwBAMAAAClLOS0AAAABGdBTUEAALGPC/xhBQAAACBj SFJNAAB6JgAAgIQAAPoAAACA6AAAdTAAAOpgAAA6mAAAF3CculE8AAAALVBMVEUifSYtgi8ngCce eyYchCE4aiVeXzDLKUviH1KkPkPbJFEhex4eeR0iaR7///9kUa2UAAAAAWJLR0QOb70wTwAAAAd0 SU1FB+UFEA0VDspxoD4AAAGUSURBVDjLbZO9TsNADMfNpQvKkvYJLlYXtkj3AhVSkVgRojvqgNgY kHiCVmRCTBU7orqJPY/QvALvgu273kcSK4ru/Mvf9vkcuJh7QwRQiFjLrgKAWgOgRlTaETHyk5Pf oMCZQiWgCZ5oAkwBE4CCGDMGShQGAjJNAhp5PDBO75KnClMYJ8BB8KI5Kzh7SpoYKhNk5zCTQHOJ 4YixWkxq9UA7RQXTB68rmLLxObLko1hyH3oyA19wVlVC9AQgoqncZjoYhCYWqwDqhQDfkPU2yxG+ mm12Z4krihey/fq5T6ut/KzAZWtfVxBHUVZaQXGwdn/nd+Sn2eUlwm1r7fGDAJ+B/HOn1bMnS+DR Z0aZdgE3JLDvK9c/xX+CA7NnFnyyW3GKs0Kv31iA0eTHIbLh1C/RX3NyApJ6vxgCkNzH7yySD4UH 224TQBJXFV61u+sU4MJ3Rx+2KgPSPyp/+ZAL3IVwd5ZDvxsfRUiGVvHaT4m7WoXxYsFHKuEX+Bla 2Z+6rgQY4VPPhK3supT89X3fBYPA/gGhXXr1ewIzvQAAACV0RVh0ZGF0ZTpjcmVhdGUAMjAyMS0w NS0xNlQxMzoyMToxNCswMDowMF6HVuUAAAAldEVYdGRhdGU6bW9kaWZ5ADIwMjEtMDUtMTZUMTM6 MjE6MTQrMDA6MDAv2u5ZAAAAAElFTkSuQmCC X-Now-Playing: Gil Scott-Heron & Jamie Xx's _We're New Here_: "Parents [Interlude]" In-Reply-To: <83a6oy20bj.fsf@gnu.org> (Eli Zaretskii's message of "Thu, 13 May 2021 17:08:32 +0300") 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:206661 Archived-At: Eli Zaretskii writes: > Looks like some memory problem: xrealloc segfaults. > > Don't we need to disable ASLR for unexec to work? And doesn't that > require setfattr or paxctl commands to be available? If not, how do > we disable ASLR in bootstrap-emacs and emacs binaries on GNU/Linux? Hm... the PROBLEMS file has this: ---- These segfaults should not occur on most modern systems, because the Emacs build procedure uses the command 'setfattr' or 'paxctl' to mark the Emacs executable as requiring non-randomized address space, and Emacs uses the 'personality' system call to disable address space randomization when dumping. ---- Is that correct? I thought we had ASLR switched on on GNU/Linux builds? ---- To work around the ASLR problem in either an older or a newer kernel, you can temporarily disable the feature while building Emacs. On GNU/Linux you can do so using the following command (as root). echo 0 > /proc/sys/kernel/randomize_va_space ---- I tried this recipe now on Debian/bullseye, but the unexec build still segfaults. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog: http://lars.ingebrigtsen.no