On Thu, Apr 12, 2012 at 7:18 PM, Kristof Provost <kristof@sigsegv.be> wrote: Hi Kristof
On 2012-04-12 18:16:56 (+0800), harryxiyou <harryxiyou@gmail.com> 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