Re: Interesting race condition...

P. Benie
2004-07-23T10:04:46Z

On Fri, 23 Jul 2004, Rob Landley wrote:

> I just saw a funky thing. Here's the cut and past from the xterm...
>
> [root@(none) root]# ps ax | grep hack
> 9964 pts/1 R 0:00 grep hack HOSTNAME= SHELL=/bin/bash TERM=xterm HISTSIZE=1000 USER=root LS_COLORS=no=00:fi=00:di=00;34:ln=00;36:pi=40;33:so=00;35:bd=40;33;01:cd=40;33;01:or=01;05;37;41:mi=01;05;37;41:ex=00;32:*.cmd=00;32:*.exe=00;32:*.com=00;32:*.btm=00;32:*.bat=00;32:*.sh=00;32:*.csh=00;32:*.tar=00;31:*.tgz=
> [root@(none) root]# ps ax | grep hack
> 9966 pts/1 S 0:00 grep hack
>
> Seems like some kind of race condition, dunno if it's in Fedore Core 1's ps
> or the 2.6.7 kernel or what...

The race is in the shell's pipeline - the processes don't start at exactly
the same time, and sometimes ps has completed before the shell has
started grep. This is the expected behaviour.

Peter