Forkbomb??

[Simon Santoro]

Karl Hegbloom wrote:
> On Sat, 2005-03-19 at 14:10 +0100, Simon Santoro wrote:
> 
>>Michael Hipp wrote:
>>
>>>Putting a limiting value on procs would help everyone and likely harm 
>>>no-one.
>>
>>I don't agree here. What if a program is designed to make a lot of 
>>forks, for example to solve a math problem (factorize big numbers) or 
>>something like that. That program could not run anymore.

> Why would a factoring program fork that many times?  What advantage
> would it gain, computationally, on a single or even dual processor
> system? 

It was only an example. Say you want to factorize 100000 numbers at one 
time. I would write a shell script that forks /usr/bin/factor 100000 
times. Would be no problem for my computer, but with the proc limit in 
place, it would not work "out of the box".

> Forking more times than there are CPU's would not gain much.

Maybe not for a computational advantage, but it could be more easy to 
write the program like that, instead of doing all the processing in a 
single thread.

> In fact, it would increase process switching and interprocess
> communication overhead.  Perhaps a parallel algorithm exists for
> factoring or matrix operations, but surely it would not need thousands
> of threads or processes to do it's job on a limited number of CPUs.

Whatever. I don't really care. As sad before, I can always change it for 
me. I still think it is impossible to save a clueless user that executes 
scripts on his local machine from untrusted sources, and thus, cutting 
down the number of procs my computer is allowed to execute at one time 
is useless and limits my available resources for no real security gain.
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