[PATCH v5 17/22] usb: dwc2: host: spinlock urb_enqueue

[Mian Yousaf Kaukab <yousaf.kaukab@xxxxxxxxx>]

From: Gregory Herrero <gregory.herrero@xxxxxxxxx>

During urb_enqueue, if the urb can't be queued to the endpoint,
the urb is freed without any spinlock protection.
This leads to memory corruption when concurrent urb_dequeue try to free
same urb->hcpriv.
Thus, ensure the whole urb_enqueue in spinlocked.

Acked-by: John Youn <johnyoun@xxxxxxxxxxxx>
Signed-off-by: Gregory Herrero <gregory.herrero@xxxxxxxxx>
---
 drivers/usb/dwc2/hcd.c       | 15 ++++++---------
 drivers/usb/dwc2/hcd_queue.c |  8 +-------
 2 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index 780f298..d72557c 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -357,12 +357,12 @@ void dwc2_hcd_stop(struct dwc2_hsotg *hsotg)
 	writel(0, hsotg->regs + HPRT0);
 }
 
+/* Caller must hold driver lock */
 static int dwc2_hcd_urb_enqueue(struct dwc2_hsotg *hsotg,
 				struct dwc2_hcd_urb *urb, void **ep_handle,
 				gfp_t mem_flags)
 {
 	struct dwc2_qtd *qtd;
-	unsigned long flags;
 	u32 intr_mask;
 	int retval;
 	int dev_speed;
@@ -413,11 +413,9 @@ static int dwc2_hcd_urb_enqueue(struct dwc2_hsotg *hsotg,
 			 */
 			return 0;
 
-		spin_lock_irqsave(&hsotg->lock, flags);
 		tr_type = dwc2_hcd_select_transactions(hsotg);
 		if (tr_type != DWC2_TRANSACTION_NONE)
 			dwc2_hcd_queue_transactions(hsotg, tr_type);
-		spin_unlock_irqrestore(&hsotg->lock, flags);
 	}
 
 	return 0;
@@ -2484,7 +2482,7 @@ static int _dwc2_hcd_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
 				"%s: unaligned transfer with no transfer_buffer",
 				__func__);
 			retval = -EINVAL;
-			goto fail1;
+			goto fail0;
 		}
 	}
 
@@ -2512,7 +2510,6 @@ static int _dwc2_hcd_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
 
 	spin_lock_irqsave(&hsotg->lock, flags);
 	retval = usb_hcd_link_urb_to_ep(hcd, urb);
-	spin_unlock_irqrestore(&hsotg->lock, flags);
 	if (retval)
 		goto fail1;
 
@@ -2521,22 +2518,22 @@ static int _dwc2_hcd_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
 		goto fail2;
 
 	if (alloc_bandwidth) {
-		spin_lock_irqsave(&hsotg->lock, flags);
 		dwc2_allocate_bus_bandwidth(hcd,
 				dwc2_hcd_get_ep_bandwidth(hsotg, ep),
 				urb);
-		spin_unlock_irqrestore(&hsotg->lock, flags);
 	}
 
+	spin_unlock_irqrestore(&hsotg->lock, flags);
+
 	return 0;
 
 fail2:
-	spin_lock_irqsave(&hsotg->lock, flags);
 	dwc2_urb->priv = NULL;
 	usb_hcd_unlink_urb_from_ep(hcd, urb);
-	spin_unlock_irqrestore(&hsotg->lock, flags);
 fail1:
+	spin_unlock_irqrestore(&hsotg->lock, flags);
 	urb->hcpriv = NULL;
+fail0:
 	kfree(dwc2_urb);
 
 	return retval;
diff --git a/drivers/usb/dwc2/hcd_queue.c b/drivers/usb/dwc2/hcd_queue.c
index bb97838..63207dc 100644
--- a/drivers/usb/dwc2/hcd_queue.c
+++ b/drivers/usb/dwc2/hcd_queue.c
@@ -761,6 +761,7 @@ void dwc2_hcd_qtd_init(struct dwc2_qtd *qtd, struct dwc2_hcd_urb *urb)
 
 /**
  * dwc2_hcd_qtd_add() - Adds a QTD to the QTD-list of a QH
+ *			Caller must hold driver lock.
  *
  * @hsotg:        The DWC HCD structure
  * @qtd:          The QTD to add
@@ -777,7 +778,6 @@ int dwc2_hcd_qtd_add(struct dwc2_hsotg *hsotg, struct dwc2_qtd *qtd,
 		     struct dwc2_qh **qh, gfp_t mem_flags)
 {
 	struct dwc2_hcd_urb *urb = qtd->urb;
-	unsigned long flags;
 	int allocated = 0;
 	int retval;
 
@@ -792,15 +792,12 @@ int dwc2_hcd_qtd_add(struct dwc2_hsotg *hsotg, struct dwc2_qtd *qtd,
 		allocated = 1;
 	}
 
-	spin_lock_irqsave(&hsotg->lock, flags);
-
 	retval = dwc2_hcd_qh_add(hsotg, *qh);
 	if (retval)
 		goto fail;
 
 	qtd->qh = *qh;
 	list_add_tail(&qtd->qtd_list_entry, &(*qh)->qtd_list);
-	spin_unlock_irqrestore(&hsotg->lock, flags);
 
 	return 0;
 
@@ -817,10 +814,7 @@ fail:
 					 qtd_list_entry)
 			dwc2_hcd_qtd_unlink_and_free(hsotg, qtd2, qh_tmp);
 
-		spin_unlock_irqrestore(&hsotg->lock, flags);
 		dwc2_hcd_qh_free(hsotg, qh_tmp);
-	} else {
-		spin_unlock_irqrestore(&hsotg->lock, flags);
 	}
 
 	return retval;
-- 
2.3.3

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