On 16:06 Tue 22 May , Johan Hovold wrote:
> On Tue, May 22, 2012 at 02:04:37PM +0200, Jan Safrata wrote:
> > Call Trace:
> > [<f85e7c60>] usb_wwan_dtr_rts+0x60/0xa0 [usb_wwan]
>
> This is not right. You're fixing a race with disconnect in option's
> probe, but this indicates that there's a race with usb_wwan_dtr_rts (as
> well).
>
> > @@ -1478,10 +1478,14 @@ static int option_send_setup(struct usb_serial_port *port)
> > struct usb_wwan_intf_private *intfdata =
> > (struct usb_wwan_intf_private *) serial->private;
> > struct usb_wwan_port_private *portdata;
> > - int ifNum = serial->interface->cur_altsetting->desc.bInterfaceNumber;
> > + int ifNum;
> > int val = 0;
> > dbg("%s", __func__);
> >
> > + if (serial->disconnected)
> > + return -ENODEV;
> > +
> > + ifNum = serial->interface->cur_altsetting->desc.bInterfaceNumber;
> > if (is_blacklisted(ifNum, OPTION_BLACKLIST_SENDSETUP,
> > (struct option_blacklist_info *) intfdata->private)) {
> > dbg("No send_setup on blacklisted interface #%d\n", ifNum);
>
> This is not quite right. You need to use the disconnect mutex as well,
> e.g.:
>
> mutex_lock(&serial->disc_mutex);
> if (serial->disconnected) {
> mutex_unlock(&serial->disc_mutex);
> return -ENODEV;
> }
> ifNum = serial->interface->cur_altsetting->desc.bInterfaceNumber;
> ...
> ret = usb_control_msg(serial->dev, ...)
> mutex_unlock(&serial->disc_mutex);
>
> return ret;
>
> Johan
The mutex cannot be used in the option_send_setup() function, because it
is already held in usb_wwan_dtr_rts() which calls the option_send_setup(),
so simple check of serial->disconnected flag should be ok there.
Best regards,
Jan
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