Re: [RFC]Something wrong with my module

[Kristof Provost <kristof@xxxxxxxxxx>]

On 2012-04-12 18:16:56 (+0800), harryxiyou <harryxiyou@xxxxxxxxx> wrote:
> Hi greg,
> 
>     I write a module for inserting a PCB or delete a PCB to kernel's
> PCB tree, but when i run it something wrong happens to me like following.
> My environment is "Linux 10 2.6.35-22-generic #33-Ubuntu SMP Sun Sep
> 19 20:34:50 UTC 2010 i686 GNU/Linux"
> 
> 	
> 	printk("Search for insert task-------->\n");
> 	task = &init_task;
> 	list_for_each(pos, &task->tasks) {
> 		p = list_entry(pos, struct task_struct, tasks);
> 		count++;
> 		if (0 == p->pid) {
> 			rm_task(p);
> 		}
> 		printk("pid: %d, state: %ld, comm: %s\n", p->pid, p->state, p->comm);
> 	}
>
You're iterating over the tasks list without locking it.

What do you think happens if someone else comes along and modifies it
while you're reading it?

Try to take the tasklist_lock.

Regards,
Kristof


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