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: dbac5d07d13e ("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>

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index a02c29216955a551cb5772dc70913f97e13eddb3..bc45077811679698388ff6366a2af8c276c56a99 100644 (file)
--- a/drivers/usb/musb/musb_host.c
+++ b/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);