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
