> 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?
> >
> > > > Yup. Fixed. Tested. Works.
> >
> > > > This patch fixes the Oops that otherwise occurs whenever
> > > > a USB serial adapter is unplugged from a system, as well
> > > > the Oops seen when one is in use before resume (to RAM).
> >
> > > Argh, no, this change was done to help the ftdi drivers out.
> >
> > > Look at changeset d9a7ecacac5f8274d2afce09aadcf37bdb42b93a in Linus's
> > > tree from Jim Radford:
> > >
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d9a7ecacac...
> > >
> > > It makes this change because the usb-serial drivers need the port
> > > devices when the port_remove() callbacks happen. Otherwise you get an
> > > oops that way.
> >
> > > Jim, can you take a look at this and see if you can figure something
> > > out?
> >
> > The problem is really the
> >
> > serial->port[i] = NULL;
> >
> > line after device_unregister() which is used to flag "fake" devices
> > that don't need legacy cleanup later in the destrol_serial. That
> > flagging should be done using a *real* flag, and not by overloading
> > the ->port[i] pointer since we require it to be non-NULL in
> > ->shutdown() in all drivers that are not converted to new
> > ->port_probe()/->port_remove() framework (currently all except ftdi).
>
> > I'll work on a patch to do that, but for now, I think you should apply
> > Mark's patch to revert the order change since the FTDI driver no
> > longer requires the correct ordering of device_unregister() and
> > ->shutdown().
>
> 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.
>
> Signed-Off: Jim Radford <radford@blackbean.org>
>
> diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
> index 8511352..871c9a8 100644
> --- a/drivers/usb/serial/usb-serial.c
> +++ b/drivers/usb/serial/usb-serial.c
> @@ -145,7 +145,6 @@ static void destroy_serial(struct kref *kref)
> 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;
> }
