Changing the state of a process

[Rajaram Suryanarayanan <rajaram_linux@xxxxxxxxx>]

 Hi,

I wrote a simple kernel module to play with the process descriptor structure of a process. I have given the code below.

int init_module(void)
{

 printk(KERN_INFO "Hello Process \n");
 printk(KERN_INFO "Parent process ID :%d \n",current->parent->pid);
 printk(KERN_INFO "Parent process state :%d \n",current->parent->state);
 printk(KERN_INFO "Parent process uid :%d \n",current->parent->uid);
 printk(KERN_INFO "Parent process priority :%d \n",current->parent->prio);

 /* Change the parent process state to unrannable */
 current->parent->state= -1;
 return 0;

}

By this code, I am trying to print the details of the parent process of the current process ( current process is insmod and its parent process is the bash shell from which I issued insmod command, if I am not wrong ). Also I try to change the state of the bash shell to -1 ( unrunnable ).

I see that the current->parent->state is printed as 1 . I see that process state > 0 is stopped , as defined in "struct task_struct". Then why it is printed as 1 when the bash shell is actually running ?

Also by changing the state of the bash shell to -1, I expected it to hang or something like that. But that did not happen.

Could anyone please let me know what is wrong with my approach..?

Thanks,
Rajaram.

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