[PATCH 6.1 078/131] usb: musb: Get the musb_qh poniter after musb_giveback

Greg Kroah-Hartman
2023-10-16T09:00:24Z

From: Xingxing Luo <xingxing.luo@unisoc.com>

commit 33d7e37232155aadebe4145dcc592f00dabd7a2b upstream.

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>
---
drivers/usb/musb/musb_host.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

--- 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_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_h
* 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);