[DragonFlyBSD - Bug #2349] fork() after signal(SIGCHLD, SIG_IGN) produces zombies

Tue Apr 17 14:17:25 PDT 2012

Issue #2349 has been updated by Max Herrgard.

On Tue, Apr 17, 2012 at 01:11:09PM -0700, Matthias Rampke via Redmine wrote:
> The code in the attached zombifier.c makes every exiting child into a zombie on master[1]. This doesn't happen on any non-DragonFly system I could test it on, and from what I gather from this discussion[2] and what Wikipedia says about SUSv3/POSIX-1.2001 the correct behaviour is not to keep them around if the SIGCHLD handler is explicitly set to SIG_IGN.
> 
> This has realworldly bitten me because the FCGI-to-CGI-wrapper I use[4] relies on this behaviour and I couldn't SSH into my server as a non-root user due to PID exhaustion.

Hm, maybe this could be the same reason why I keep getting zombies with firefox, thunderbird and xpdf all the time.

Max
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Bug #2349: fork() after signal(SIGCHLD, SIG_IGN) produces zombies
http://bugs.dragonflybsd.org/issues/2349

Author: Matthias Rampke
Status: New
Priority: Normal
Assignee: 
Category: 
Target version: 

The code in the attached zombifier.c makes every exiting child into a zombie on master[1]. This doesn't happen on any non-DragonFly system I could test it on, and from what I gather from this discussion[2] and what Wikipedia says about SUSv3/POSIX-1.2001 the correct behaviour is not to keep them around if the SIGCHLD handler is explicitly set to SIG_IGN.

This has realworldly bitten me because the FCGI-to-CGI-wrapper I use[4] relies on this behaviour and I couldn't SSH into my server as a non-root user due to PID exhaustion.

[1] DragonFly zz.2pktfkt.net 3.1-DEVELOPMENT DragonFly v3.1.0.545.g4c42b-DEVELOPMENT #6: Tue Apr 17 21:24:31 CEST 2012     matthias at zz.2pktfkt.net:/usr/obj/usr/src/sys/X86_64_GENERIC  x86_64
[2] http://markmail.org/message/3s4jj7dpgw34yvmh
[3] http://en.wikipedia.org/wiki/Zombie_process
[4] http://pkgsrc.se/wip/fcgiwrap

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