usb: musb: Get the musb_qh poniter after musb_giveback

When multiple threads are performing USB transmission, musb->lock will be
unlocked when musb_giveback is executed. At this time, qh may be released
in the dequeue process in other threads, resulting in a wild pointer, so
it needs to be here get qh again, and judge whether qh is NULL, and when
dequeue, you need to set qh to NULL.

Fixes: dbac5d0 ("usb: musb: host: don't start next rx urb if current one failed")
Cc: stable@vger.kernel.org
Signed-off-by: Xingxing Luo <xingxing.luo@unisoc.com>
Link: https://lore.kernel.org/r/20230919033055.14085-1-xingxing.luo@unisoc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Xingxing Luo

drivers/usb/musb/musb_host.c

@@ -321,10 +321,16 @@ static void musb_advance_schedule(struct musb *musb, struct urb *urb,
 	musb_giveback(musb, urb, status);
 	qh->is_ready = ready;
 
+	/*
+	 * musb->lock had been unlocked in musb_giveback, so qh may
+	 * be freed, need to get it again
+	 */
+	qh = musb_ep_get_qh(hw_ep, is_in);
+
 	/* reclaim resources (and bandwidth) ASAP; deschedule it, and
 	 * invalidate qh as soon as list_empty(&hep->urb_list)
 	 */
-	if (list_empty(&qh->hep->urb_list)) {
+	if (qh && list_empty(&qh->hep->urb_list)) {
 		struct list_head	*head;
 		struct dma_controller	*dma = musb->dma_controller;
 
@@ -2398,6 +2404,7 @@ static int musb_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 		 * and its URB list has emptied, recycle this qh.
 		 */
 		if (ready && list_empty(&qh->hep->urb_list)) {
+			musb_ep_set_qh(qh->hw_ep, is_in, NULL);
 			qh->hep->hcpriv = NULL;
 			list_del(&qh->ring);
 			kfree(qh);