Re: [PATCH] usb-serial regression fix

Jim Radford
2007-03-13T00:44:12Z

On Mon, Mar 12, 2007 at 05:18:19PM -0700, Greg KH wrote:
> On Mon, Mar 12, 2007 at 03:59:22PM -0700, Jim Radford wrote:
> > On Mon, Mar 12, 2007 at 03:42:35PM -0700, Jim Radford wrote:
> > > On Mon, Mar 12, 2007 at 01:33:31PM -0700, Greg KH wrote:
> > > > On Mon, Mar 12, 2007 at 04:22:22PM -0400, Mark Lord wrote:
> > > > > Oliver Neukum wrote:
> > > > > > >Mark Lord wrote:
> > > > > > > >Okay, from that part (above), the problem is obvious:
> > > > > > > >in that the "MCT U232 converter now disconnected"
> > > > > > > >appears, and then we continue to try and call the
> > > > > > > >driver's method.. Oops!

> > > > > >IMHO shutdown() is using serial->port[] and bombs.
> > > > > >Could you reverse the order here?

> > Do not NULL serial->port[i] since it is used in ->shutdown().
> > This wasn't an issue until the order or ->shutdown() and
> > device_unregister was corrected.

> > for (i = 0; i < serial->num_ports; ++i)
> > if (serial->port[i]->dev.parent != NULL) {
> > device_unregister(&serial->port[i]->dev);
> > - serial->port[i] = NULL;
> > }

> But shouldn't you null it out somewhere? It will be an "empty"
> pointer at some point in time...

Not as far as I can see. The serial structure that ->port[i] is in
gets kfree()ed soon after, in the same function, and nothing in
between, other than ->shutdown(), uses ->port[]. I assume it was
someone being overly cautious.

-Jim