Re: Query: Real time process

[Chetan Nanda <chetannanda@xxxxxxxxx>]

On Sun, Mar 22, 2009 at 1:48 PM, Sandeep K Sinha <sandeepksinha@xxxxxxxxx> wrote:

On Sun, Mar 22, 2009 at 1:38 PM, Chetan Nanda <chetannanda@xxxxxxxxx> wrote:
> Hi All,
>
> I am experimenting with real time process on kernel version 2.6.24 (under
> UML) and having root privileges.
> I have written a simple code as follow:
>
> /*##############################*/
> int main()
> {
>     pid_t pid;
>     struct sched_param param;
>     pid = getpid();
>     memset((void *)&param, 0 , sizeof(struct sched_param));
>     param.sched_priority = 30;
>
>     /*change the priority to rt*/
>     sched_setscheduler(pid,SCHED_FIFO, &param);
>
>     while(1);
> }
> /*##############################*/
>
> On running this program cause system to hangs and this is as per the real
> time task implementation in the kernel.
> Which says a rt task with policy equal to 'SCHED_FIFO' will run till it
> voluntarily release CPU.
>
> Is there any way to kill such task? Isn't this kind of behavior compromising
> system security?
>

AFAIK, No.

And as far as the security is concerned, only a super user can run
this task. Meaning that the user has the authority to do such things.

Suppose, If kernel is PID Namespace aware, and root user in one namespace run this kind of task then, (I think) whole system will come to halt. Is my understanding on this correct? 

> ~~
> Chetan Nanda
>



--
Regards,
Sandeep.






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