From b3207c65dfafae27e7c492cb9188c0dc0eeaf3fd Mon Sep 17 00:00:00 2001
From: Mayank Rana <mrana@codeaurora.org>
Date: Fri, 6 Oct 2017 17:45:30 +0300
Subject: [PATCH] usb: xhci: Handle error condition in xhci_stop_device()
Git-commit: b3207c65dfafae27e7c492cb9188c0dc0eeaf3fd
Patch-mainline: v4.14-rc6
References: bsc#1085536

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.

Fixes: c311e391a7ef ("xhci: rework command timeout and cancellation,")
Cc: <stable@vger.kernel.org>
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/host/xhci-hub.c |   20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -412,15 +412,23 @@ static int xhci_stop_device(struct xhci_
 						     GFP_NOWAIT);
 			if (!command) {
 				spin_unlock_irqrestore(&xhci->lock, flags);
-				xhci_free_command(xhci, cmd);
-				return -ENOMEM;
-
+				ret = -ENOMEM;
+				goto cmd_cleanup;
 			}
-			xhci_queue_stop_endpoint(xhci, command, slot_id, i,
+			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, 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);
 
@@ -432,6 +440,8 @@ static int xhci_stop_device(struct xhci_
 		xhci_warn(xhci, "Timeout while waiting for stop endpoint command\n");
 		ret = -ETIME;
 	}
+
+cmd_cleanup:
 	xhci_free_command(xhci, cmd);
 	return ret;
 }