zsh can causes ps to generate error message

[James Hunt]

(ps|grep foo;echo)
Signal 18 (CONT) caught by ps (procps-ng version 3.3.3).
ps:display.c:59: please report this bug

(ps;echo) # works
(ps|grep foo) # works
(ps|grep foo;echo) # fails

This behaviour seems to be caused by zsh since it is not observable using bash. Note too that this bug cannot be recreated on precise.

zsh configuration is stock "system configuration" (run zsh for first time and select option (2) - system defaults).

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: zsh 5.0.0-2ubuntu1
ProcVersionSignature: Ubuntu 3.5.0-15.22-generic 3.5.4
Uname: Linux 3.5.0-15-generic i686
ApportVersion: 2.5.2-0ubuntu4
Architecture: i386
Date: Mon Sep 24 16:01:37 2012
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha i386 (20120530)
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/zsh
SourcePackage: zsh
UpgradeStatus: No upgrade log present (probably fresh install)

[Axel Beckert (xtaran)]

The output "ps:display.c:59: please report this bug" is from procps-ng, so I'd suspect it's rather an issue in procps-ng than in zsh.

The difference to bash is possible caused by differences about when subshells are spawned and when not -- an area where the POSIX specification is ambiguous and hence different behaviour is to be expected.

I can also reproduce this issue with zsh from Debian Experimental (on which Quantal's zsh package is based upon) and with zsh in Debian Unstable and Testing (on which Precise's zsh package is based upon). In those case procps 1:3.3.3-2 where used. But Precise has 1:3.2.8-11ubuntu6, so I guess the difference is rather the procps than the zsh version. Reassigning.

[taco (halstonc)]

I'm getting the same procps-ng error

$ ps
Signal 11 (SEGV) caught by ps (procps-ng version 3.3.3).
ps:display.c:59: please report this bug
$ dpkg --list procps
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-=======================-================-================-====================================================
ii procps 1:3.3.3-2ubuntu5 amd64 /proc file system utilities
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 13.04
Release: 13.04
Codename: raring

I found a Debian bug report for the same issue (I think).
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=704041

Can we move to the latest version of procps?

[Ihar Hrachyshka (ihar-hrachyshka)]

I think it was fixed in Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=732410

[Axel Beckert (xtaran)]

Yes, this does no more appear in at least 16.04 Xenial. And Xenial has procps 3.3.10 which should have fixed this issue. Hence closing. Thanks for the hint.