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@xxxxxxxxxxxxxxx
Signed-off-by: Xingxing Luo <xingxing.luo@xxxxxxxxxx>
---
v2 -> v3: Add Cc: stable
v1 -> v2: - Modified the comments section.
- Modified "if (qh != NULL && ..." to "if (qh && ...".
drivers/usb/musb/musb_host.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index a02c29216955..bc4507781167 100644
--- 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);
--
2.17.1
