Re: Is it possible to give the user the option to cancel forkbombs?

(``-_-´´) -- Fernando
2007-11-22T09:38:37Z

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On Saturday 17 November 2007 07:04:48 Martin Olsson wrote:
> Repro steps:
>
> 1. Install gutsy gibbon (or probably any ubuntu)
> 2. Start a gnome terminal
> 3. Run this command:
>
> :(){ :|:& };:
>
> 4. Ubuntu starts to work furiously, after less than a second terminal
> gets flooded with "low resources" message, and within a few seconds the
> whole machine breaks down complete to the point where no a single pixel
> is updated and the mouse cannot be moved at all. It's not possible to
> escape to a ALT-Fn console terminal and CTRL-ALT-DEL does not work.
>
> Okay, so this is not as bad as winnuke.exe because it's not remote but I
> just did it on my shared hosting co and their server went down. And I
> mean seriously, there should be a way for a user to abort stuff that
> hogs resources this type of complete breakdown is NEVER acceptible. I
> had to power of the machine and my file system got royally screwed (long
> fsck etc).
>
> Some of you might say this is like the oldest trick in the book, yada
> yada yada...
>
> Martin

I used to see stuff like this happening on my University students test servers. Once they started doing forks inside for(;;), the server would go down.
Then they replaced the servers by vwmare machines, and now reboots are faster.

But I would like to see installed by default some script like AND(Auto Nice Daemon) or CpuLimit locking any and every process to a maximum of 90% after X seconds. That way one could allways launch a new command and kill it.
Of course, this is assuming that disk I/O is not our main prob, 'cause if that happens there's no way out.

--
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