Fork Bomb

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Re: Fork Bomb
We can't see that image. That top line only works for people sat at your PC. It doesn't work over the internet.

Use a service like photobucket or even facebook to hold the image online then give us the URL of the image. We can then see what you want us to see
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1 Week Ago#3Holger_Gehrke Holger_Gehrke is offline
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Re: Fork Bomb
A fork bomb is basically a recursion without a stop condition. To stop fork bombs from taking all resources on the system, you need to limit the allowed depth of recursions. 'ulimit' doesn't have a setting specifically for this, although the maximum stack size ('-s') might do some good. There is a variable FUNCNEST which can be set to the maximum acceptable calling depth. This does not just limit recursions it limits all functions calling functions, so you should not set this limit too low.

Holger
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Re: Fork Bomb
Rebooting should stop a fork bomb. But if it starts running as a result of compromise, things may become difficult.

You certainly don't want the maximum number of processes to be unlimited. The fork bomb will just fill them up.

Is this a personal machine? A work machine?

Admins will sometimes use a fork bomb in pen testing.
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Re: Fork Bomb
Rebooting is the only option to stop this . Its a recording server in night time when nobody monitors the server at that time we loose valuable recording due to this.
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Re: Fork Bomb
kindly guide how to go with maximum stack size
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1 Week Ago#7Holger_Gehrke Holger_Gehrke is offline
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Re: Fork Bomb
That's probably not a fork bomb. The error message says something about a resource not being available. Looks more like it's trying to restart something after it crashed before the clean-up was completely done. Posting the script that produces this error might give us enough insight into what's going on to attempt a solution.

Holger
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1 Week Ago#8Rubi1200's AvatarRubi1200 Rubi1200 is online now
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Re: Fork BombI agree with Holger that seeing what script/s are being run can help us with solutions. But, I also have a question: you say this is a recording server but it appears to have a GUI; why is that?

From a security standpoint, this is not considered to be good practice.
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Re: Fork BombIts a normal ubuntu server & some java application running on it & nothing running with script . Its a 24*7 environment as it runs suddenly while in operation we encounter this issue.
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1 Week Ago#10Holger_Gehrke Holger_Gehrke is offline
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Re: Fork BombI may not know all the Java applications around, but almost all of the non-trivial ones I've seen were started by a script which sets all the options for the VM and performed various house-keeping tasks before actually starting the application. You seem to underestimate how deeply scripting - and especially shell scripting - is embedded in the Linux and Unix way of doing things. For example there's more than 300 shell scripts (counted by doing 'for i in /usr/bin/*; do file $i|grep shell;done|wc -l') out of less than 2800 files in /usr/bin on my machine.

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