On Thu, Apr 12, 2012 at 7:18 PM, Kristof Provost <kristof@xxxxxxxxxx> wrote:
Hi Kristof
> 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?
Hmmm, Yes, i should lock it.
>
> Try to take the tasklist_lock.
I will try, thanks.
--
Thanks
Harry Wei
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