Freeing work_struct memory

Freeing work_struct memory

[Kai Meyer]

I've got a bug I'm having trouble identifying. It seems like it could be 
related to my work_struct usage. I essentially have this:

struct my_worker {
         work_struct work;
         /* some other data */
};

void worker_fn(struct work_struct *work)
{
         struct my_worker *worker = container_of(work, struct my_worker, 
work);
         /* ... do some stuff ... */
         kfree(worker);
}

void worker_caller()
{
         struct my_worker *worker = kmalloc(sizeof(*worker), GFP_KERNEL);
         INIT_WORK(&worker->work, worker_fn);
         /* ... add some other stuff to *worker ... */
         schedule_work(&worker->work);
}

I frequently get a kernel panic with a specific test, but the stack 
trace is rarely the same, which seems to indicate to me that I'm 
corrupting data somewhere. So my question is:

Can I free the memory for "struct my_worker *worker" inside worker_fn? 
Or does the work_queue stuff need to continue to use the "struct 
work_struct work" member after the end of worker_fn?

-Kai Meyer

Freeing work_struct memory

[Mulyadi Santosa]

Hi ...

On Tue, Nov 22, 2011 at 03:55, Kai Meyer <kai@gnukai.com> wrote:
> I frequently get a kernel panic with a specific test, but the stack
> trace is rarely the same, which seems to indicate to me that I'm
> corrupting data somewhere. So my question is:
>
> Can I free the memory for "struct my_worker *worker" inside worker_fn?
> Or does the work_queue stuff need to continue to use the "struct
> work_struct work" member after the end of worker_fn?

I think it's due to the dequeueing out of the worker thread. So, it
tries to dequeue, but in fact it points to NULL.

You need to make sure it finishes completely first...then free it later.

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com