From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Robert Pluim Newsgroups: gmane.emacs.bugs Subject: bug#36279: 26.2.90; (process-attributes nonexistent-pid) segmentation fault Date: Tue, 18 Jun 2019 17:23:08 +0200 Message-ID: References: <87zhmfvx44.fsf@gmail.com> <42c23bd8-57e3-4503-a6cf-d38aec89edd0@www.fastmail.com> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="76364"; mail-complaints-to="usenet@blaine.gmane.org" Cc: 36279@debbugs.gnu.org, Noam Postavsky To: xuchunyang Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Tue Jun 18 18:25:32 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 (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hdGvL-000Jhc-PV for geb-bug-gnu-emacs@m.gmane.org; Tue, 18 Jun 2019 18:25:31 +0200 Original-Received: from localhost ([::1]:59550 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdGvK-0005Nq-Ki for geb-bug-gnu-emacs@m.gmane.org; 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Tue, 18 Jun 2019 08:23:09 -0700 (PDT) Mail-Copies-To: never Gmane-Reply-To-List: yes In-Reply-To: <42c23bd8-57e3-4503-a6cf-d38aec89edd0@www.fastmail.com> (xuchunyang's message of "Tue, 18 Jun 2019 22:05:38 +0800") X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.51.188.43 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.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:160773 Archived-At: >>>>> On Tue, 18 Jun 2019 22:05:38 +0800, xuchunyang said: xuchunyang> On Tue, Jun 18, 2019, at 9:31 PM, Noam Postavsky wrote: >> Xu Chunyang writes: >> >> > Emacs crashes when I run the following (the PID 123456 doesn't exist) >> > >> > (process-attributes 123456) >> > >> > And I can reproduce it from Emacs -Q: >> > >> > ~ $ emacs -Q --batch --eval '(print (process-attributes 123456))' >> > Fatal error 11: Segmentation faultzsh: segmentation fault emacs -Q --batch --eval '(print (process-attributes 123456))' >> > ~ $ emacs --version | head -1 >> > GNU Emacs 26.2.90 >> > ~ $ >> > >> > >> > In GNU Emacs 26.2.90 (build 1, x86_64-apple-darwin18.6.0, Carbon Version 158 AppKit 1671.5) >> >> Doesn't happen here[1], I just get nil. Can you show a backtrace with a >> gdb (or lldb if that's not available)? I get the same crash here. You'd expect sysctl to return an error when requesting info about a non-existent process, but instead it passive-agressively sets proclen to 0. This fixes it for me here, can you try it? diff --git a/src/sysdep.c b/src/sysdep.c index 1e35e06b63..518ecebcf6 100644 --- a/src/sysdep.c +++ b/src/sysdep.c @@ -3798,7 +3798,7 @@ system_process_attributes (Lisp_Object pid) CONS_TO_INTEGER (pid, int, proc_id); mib[3] = proc_id; - if (sysctl (mib, 4, &proc, &proclen, NULL, 0) != 0) + if (sysctl (mib, 4, &proc, &proclen, NULL, 0) != 0 || proclen == 0) return attrs; uid = proc.kp_eproc.e_ucred.cr_uid;