On Mon, 16 Nov 2020, Johan Hovold wrote:
On Fri, Nov 13, 2020 at 08:27:25PM -0800, Davidlohr Bueso wrote:
@@ -1883,21 +1724,17 @@ static void mos7720_release(struct usb_serial *serial)
if (mos_parport->msg_pending)
wait_for_completion_timeout(&mos_parport->syncmsg_compl,
msecs_to_jiffies(MOS_WDR_TIMEOUT));
+ /*
+ * If delayed work is currently scheduled, wait for it to
+ * complete. This also implies barriers that ensure the
+ * below serial clearing is not hoisted above the ->work.
+ */
+ cancel_work_sync(&mos_parport->work);
As I mentioned, this needs to be done *after* deregistering the port or
you could theoretically end up with the work item being requeued.
Hmm sorry yes I forgot to mention this. I was counting on the private_data
already being null to prevent any new work being actually scheduled, so an
incoming restore state, for example, would be a nop.
Yes, the same applies for the "synchronous" requests, but that's a
preexisting issue.
Per the above I also assumed sync requests were also safe as is.
But I can certainly re-order things, how about:
mos7720_release():
mos_parport->pp->private_data = NULL;
parport_remove_port(mos_parport->pp);
wait_for_completion_timeout();
cancel_work_sync();
usb_set_serial_data(serial, NULL);
mos_parport->serial = NULL;
parport_del_port(mos_parport->pp);
kref_put();
Thanks,
Davidlohr
