Re: [PATCH] usb-serial regression fix

[Mark Lord]

Jim Radford wrote:
> 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.

So where does the memory get freed -- the structure pointed at
by the serial->port[i] thingie ?  It's not a leak, is it?

???
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