From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.bugs,gmane.linux.kernel Subject: bug#34235: 0e334db6bb4b1fd1e2d72c1f3d8f004313cd9f94 (posix-timers: Fix, division by zero bug). Problems with glibc. Date: Fri, 1 Feb 2019 18:07:09 -0800 Organization: UCLA Computer Science Department Message-ID: <17880b13-2fde-764d-a284-11cf0caf1cec@cs.ucla.edu> References: <87o9807ht0.fsf@gmail.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------3EDE60C2A864A50FA18F8A05" Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="89131"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 Cc: Alan Mackenzie , Alex Branham , 34235@debbugs.gnu.org, linux-kernel@vger.kernel.org To: Thomas Gleixner Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sat Feb 02 03:08:14 2019 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1gpkj8-000N4k-6X for geb-bug-gnu-emacs@m.gmane.org; Sat, 02 Feb 2019 03:08:14 +0100 Original-Received: from localhost ([127.0.0.1]:36159 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gpkj6-0001Z7-IV for geb-bug-gnu-emacs@m.gmane.org; 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charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Thanks for helping to track down this bug. Since the problem occurs only with a few Linux kernel versions and affects Emacs only when doing CPU profiling, it doesn't seem worth spending time to try to patch Emacs to work around the bug. So I installed the attached patch into emacs-26's etc/PROBLEMS file to warn users about the problem, and am closing the Emacs bug report. --------------3EDE60C2A864A50FA18F8A05 Content-Type: text/x-patch; name="0001-etc-PROBLEMS-Mention-profiler-report-bug-Bug-34235.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename*0="0001-etc-PROBLEMS-Mention-profiler-report-bug-Bug-34235.patc"; filename*1="h" >From 1243188bc4f722abf16518bf73924ce5f17750cf Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Fri, 1 Feb 2019 17:58:05 -0800 Subject: [PATCH] * etc/PROBLEMS: Mention profiler-report bug (Bug#34235). --- etc/PROBLEMS | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/etc/PROBLEMS b/etc/PROBLEMS index cab087631c..00583f016d 100644 --- a/etc/PROBLEMS +++ b/etc/PROBLEMS @@ -1850,6 +1850,12 @@ term/xterm.el) for more details. ** GNU/Linux +*** GNU/Linux: profiler-report outputs nothing. + +A few versions of the Linux kernel have timer bugs that break CPU +profiling; see Bug#34235. To fix the problem, upgrade to kernel +versions 4.19.19 or 4.20.6, or later. + *** GNU/Linux: Process output is corrupted. There is a bug in Linux kernel 2.6.10 PTYs that can cause emacs to -- 2.20.1 --------------3EDE60C2A864A50FA18F8A05--