Re: [PATCH] kthread: Unpark only parked kthreads (was Re: [syzbot] [wireguard?] WARNING in kthread_unpark (2))

[Hillf Danton <hdanton@sina.com>]

Test Frederic's idea.

#syz test upstream master

--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -623,6 +623,8 @@ void kthread_unpark(struct task_struct *
 {
 	struct kthread *kthread = to_kthread(k);
 
+	if (!test_bit(KTHREAD_SHOULD_PARK, &kthread->flags))
+		return;
 	/*
 	 * Newly created kthread was parked when the CPU was offline.
 	 * The binding was lost and we need to set it again.
--- l/drivers/input/misc/yealink.c
+++ y/drivers/input/misc/yealink.c
@@ -438,7 +438,7 @@ static void urb_irq_callback(struct urb
 
 	yealink_do_idle_tasks(yld);
 
-	if (!yld->shutdown) {
+	if (!yld->shutdown && status != -EPROTO) {
 		ret = usb_submit_urb(yld->urb_ctl, GFP_ATOMIC);
 		if (ret && ret != -EPERM)
 			dev_err(&yld->intf->dev,
@@ -460,13 +460,13 @@ static void urb_ctl_callback(struct urb
 	case CMD_KEYPRESS:
 	case CMD_SCANCODE:
 		/* ask for a response */
-		if (!yld->shutdown)
+		if (!yld->shutdown && status != -EPROTO)
 			ret = usb_submit_urb(yld->urb_irq, GFP_ATOMIC);
 		break;
 	default:
 		/* send new command */
 		yealink_do_idle_tasks(yld);
-		if (!yld->shutdown)
+		if (!yld->shutdown && status != -EPROTO)
 			ret = usb_submit_urb(yld->urb_ctl, GFP_ATOMIC);
 		break;
 	}
--