patch "usb: xhci: Handle error condition in xhci_stop_device()" added to usb-linus

This is a note to let you know that I've just added the patch titled

usb: xhci: Handle error condition in xhci_stop_device()

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From: Mayank Rana <[email protected]>
Date: Fri, 6 Oct 2017 17:45:30 +0300
Subject: usb: xhci: Handle error condition in xhci_stop_device()

xhci_stop_device() calls xhci_queue_stop_endpoint() multiple times without checking the return value. xhci_queue_stop_endpoint() can return error if the HC is already halted or unable to queue commands. This can cause a deadlock condition as xhci_stop_device() would end up waiting indefinitely for a completion for the command that didn't get queued. Fix this by checking the return value and bailing out of xhci_stop_device() in case of error. This patch happens to fix potential memory leaks of the allocated command structures as well.

---
 drivers/usb/host/xhci-hub.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

index da9158f171cb..a2336deb5e36 100644
@@ -420,14 +420,25 @@ static int xhci_stop_device(struct xhci_hcd *xhci, int slot_id, int suspend)
 						     GFP_NOWAIT);
 			if (!command) {
 				spin_unlock_irqrestore(&xhci->lock, flags);
-				xhci_free_command(xhci, cmd);
-				return -ENOMEM;
+				ret = -ENOMEM;
+				goto cmd_cleanup;
+			}
+
+			ret = xhci_queue_stop_endpoint(xhci, command, slot_id,
+						       i, suspend);
+			if (ret) {
+				spin_unlock_irqrestore(&xhci->lock, flags);
+				xhci_free_command(xhci, command);
+				goto cmd_cleanup;
 			}
-			xhci_queue_stop_endpoint(xhci, command, slot_id, i,
-						 suspend);
 		}
 	}
-	xhci_queue_stop_endpoint(xhci, cmd, slot_id, 0, suspend);
+	ret = xhci_queue_stop_endpoint(xhci, cmd, slot_id, 0, suspend);
+	if (ret) {
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		goto cmd_cleanup;
+	}
+
 	xhci_ring_cmd_db(xhci);
 	spin_unlock_irqrestore(&xhci->lock, flags);
 

@@ -439,6 +450,8 @@ static int xhci_stop_device(struct xhci_hcd *xhci, int slot_id, int suspend)
 		xhci_warn(xhci, "Timeout while waiting for stop endpoint command\n");
 		ret = -ETIME;
 	}
+
+cmd_cleanup:
 	xhci_free_command(xhci, cmd);
 	return ret;
 }

2.14.2