Re: [1/1] connector/CBUS: new messaging subsystem. Revision number next.

[Evgeniy Polyakov <johnpol@xxxxxxxxxxx>]

On Tue, 26 Apr 2005 12:34:13 -0500
Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> wrote:

> On 4/26/05, Evgeniy Polyakov <johnpol@xxxxxxxxxxx> wrote:
> > 
> > --- orig/drivers/connector/connector.c
> > +++ mod/drivers/connector/connector.c
> > @@ -151,8 +151,8 @@
> >                        __cbq->ddata = data;
> >                        __cbq->destruct_data = destruct_data;
> > 
> > -                       queue_work(dev->cbdev->cn_queue, &__cbq->work);
> > -                       found = 1;
> > +                       if (queue_work(dev->cbdev->cn_queue, &__cbq->work))
> > +                               found = 1;
> >                        break;
> 
> What does it help exactly? By the time you checked result of
> queue_work you have already corrupted work structure wuth the new data
> (and probably destructor).
> 
> Also, where is the rest of the code? Should we notify caller that
> cn_netlink_send has dropped the message? And how do we do that?

Yes, I found it too.
Following patch should be the solution:

--- orig/drivers/connector/connector.c
+++ mod/drivers/connector/connector.c
@@ -146,13 +146,16 @@
        spin_lock_bh(&dev->cbdev->queue_lock);
        list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
                if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
-                       __cbq->cb->priv = msg;
+       
+                       if (!test_bit(0, &work->pending)) {
+                               __cbq->cb->priv = msg;
 
-                       __cbq->ddata = data;
-                       __cbq->destruct_data = destruct_data;
+                               __cbq->ddata = data;
+                               __cbq->destruct_data = destruct_data;
 
-                       if (queue_work(dev->cbdev->cn_queue, &__cbq->work))
-                               found = 1;
+                               if (queue_work(dev->cbdev->cn_queue, 
&__cbq->work))
+                                       found = 1;
+                       }
                        break;
                }
        }


 
> -- 
> Dmitry
> 


        Evgeniy Polyakov

Only failure makes us experts. -- Theo de Raadt