From d5fc72d5b44f20856f7a27cae1dd18f9d70976fe Mon Sep 17 00:00:00 2001
From: Russ Butler <russ.butler@arm.com>
Date: Fri, 25 May 2018 11:19:34 -0500
Subject: [PATCH] Fix unbalanced USBDevice unlock

Remove calls to unlock which are not preceded by calls to lock.
Also move the location of the unlock underflow assert so unbalanced
unlocking during post processing is caught.
---
 usb/device/USBDevice/USBDevice.cpp | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/usb/device/USBDevice/USBDevice.cpp b/usb/device/USBDevice/USBDevice.cpp
index 3c73170c4b..600520af4f 100644
--- a/usb/device/USBDevice/USBDevice.cpp
+++ b/usb/device/USBDevice/USBDevice.cpp
@@ -331,13 +331,11 @@ void USBDevice::_complete_request_xfer_done()
     _transfer.user_callback = None;
     if (_abort_control) {
         _control_abort();
-        unlock();
         return;
     }
 
     if (!success) {
         _phy->ep0_stall();
-        unlock();
         return;
     }
 
@@ -405,7 +403,6 @@ void USBDevice::_complete_set_configuration()
     _transfer.user_callback = None;
     if (_abort_control) {
         _control_abort();
-        unlock();
         return;
     }
 
@@ -478,7 +475,6 @@ void USBDevice::_complete_set_interface()
     _transfer.user_callback = None;
     if (_abort_control) {
         _control_abort();
-        unlock();
         return;
     }
 
@@ -716,7 +712,6 @@ void USBDevice::_complete_request()
         } else {
             _control_abort();
         }
-        unlock();
         return;
     }
 
@@ -1563,8 +1558,6 @@ void USBDevice::lock()
 
 void USBDevice::unlock()
 {
-    MBED_ASSERT(_locked > 0);
-
     if (_locked == 1) {
         // Perform post processing before fully unlocking
         while (_post_process != NULL) {
@@ -1574,6 +1567,7 @@ void USBDevice::unlock()
         }
     }
 
+    MBED_ASSERT(_locked > 0);
     _locked--;
     core_util_critical_section_exit();
 }