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#47125: 28.0.50; pdumper assumes compile time page size remains valid Date: Sun, 14 Mar 2021 07:37:07 +0200 Message-ID: <83r1kigut8.fsf@gnu.org> References: Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="15673"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 47125@debbugs.gnu.org To: Pip Cet Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sun Mar 14 06:38:12 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 1lLJS8-00040T-J8 for geb-bug-gnu-emacs@m.gmane-mx.org; Sun, 14 Mar 2021 06:38:12 +0100 Original-Received: from localhost ([::1]:53000 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lLJS7-00021B-Ld for geb-bug-gnu-emacs@m.gmane-mx.org; Sun, 14 Mar 2021 00:38:11 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:40698) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lLJRy-000213-Sg for bug-gnu-emacs@gnu.org; Sun, 14 Mar 2021 00:38:02 -0500 Original-Received: from debbugs.gnu.org ([209.51.188.43]:49475) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lLJRy-0004Eo-Ks for bug-gnu-emacs@gnu.org; Sun, 14 Mar 2021 00:38:02 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1lLJRy-0005Tf-Hi for bug-gnu-emacs@gnu.org; Sun, 14 Mar 2021 00:38:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 14 Mar 2021 05:38:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 47125 X-GNU-PR-Package: emacs Original-Received: via spool by 47125-submit@debbugs.gnu.org id=B47125.161570022820989 (code B ref 47125); Sun, 14 Mar 2021 05:38:02 +0000 Original-Received: (at 47125) by debbugs.gnu.org; 14 Mar 2021 05:37:08 +0000 Original-Received: from localhost ([127.0.0.1]:32788 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lLJR6-0005SS-Az for submit@debbugs.gnu.org; Sun, 14 Mar 2021 00:37:08 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:51032) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lLJR4-0005S3-GD for 47125@debbugs.gnu.org; Sun, 14 Mar 2021 00:37:07 -0500 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:47839) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lLJQy-0003jo-8m; Sun, 14 Mar 2021 00:37:00 -0500 Original-Received: from 84.94.185.95.cable.012.net.il ([84.94.185.95]:4052 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1lLJQx-00015t-IO; Sun, 14 Mar 2021 00:37:00 -0500 In-Reply-To: (message from Pip Cet on Sat, 13 Mar 2021 21:38:16 +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:202326 Archived-At: > From: Pip Cet > Date: Sat, 13 Mar 2021 21:38:16 +0000 > > I'm running Debian GNU/Linux (the Linux part is not provided by > Debian) on an Apple M1-based machine. This currently involves running > a kernel compiled with a 16 KB page size (the only fully functional > kernel is currently available as a binary as recompilation of the > alleged source fails to produce a fully working kernel). > > The Debian-packaged Emacs version does not start. Compiling from > scratch works fine. > > After some investigation, this is because pdumper assumes that an > address aligned according to the page size at build time is > sufficiently aligned for mmap to work with the MAP_FIXED flag, when it > comes to loading the dump. That's not true because the Debian Emacs > was apparently built with a 4 KB page size, so it will not run on a > system with a 16 KB page size. > > I've confirmed that I get the same error on current master if I modify > getpagesize to return 4096 rather than the correct value. > > I think it would be best to handle this case gracefully, and I thought > pdumper already did that, but it appears to simply fail. > > There are good reasons for increasing the page size, so this is likely > to happen more often and on other architectures with varying page > sizes. CC'ing Daniel, in case he has comments and/or suggestions. > We're currently enforcing a page size of 64 KB on Windows We do? can you point me to the code which does that? > so maybe it already has.