Why doesn't kill work?

In another thread a user having problems with yum killed it. I am curious how he accomplished that. When I run yum (or any other command, for that matter), it stalls, and I stop it with ctrl-z, the following happens:

[1]+  Stopped                 yum update
[root@tabby ~]# ps
  PID TTY          TIME CMD
 6179 pts/0    00:00:00 su
 6182 pts/0    00:00:00 bash
 6214 pts/0    00:00:21 yum
 6220 pts/0    00:00:00 ps
[root@tabby ~]# kill 6214
[root@tabby ~]# ps
  PID TTY          TIME CMD
 6179 pts/0    00:00:00 su
 6182 pts/0    00:00:00 bash
 6214 pts/0    00:00:21 yum ##still running!
 6221 pts/0    00:00:00 ps
[root@tabby ~]# exit
logout
There are stopped jobs. ##still running!
[root@tabby ~]#

As you see, the kill command produces no output here, but if I make up a pid at random it complains no such pid exists.

I'm running a single Athlon 1 gHz processor, if that is important.

When I search Bugzilla for "kill" the only relevant hits are from ages ago in RH 5.1 or so, where a few lines of code run by a non-root user could kill any process regardless of owner (the opposite problem). This was apparently fixed and closed. I considered compiling and running the program as root to see if I had better luck than with kill, but it doesn't really address the issue.

Should I file a Bugzilla report, or am I missing something?

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David Liguori