Index: utils/lit/lit/LitConfig.py
===================================================================
--- utils/lit/lit/LitConfig.py
+++ utils/lit/lit/LitConfig.py
@@ -120,6 +120,17 @@
         if self.bashPath is None:
             self.bashPath = ''
 
+        # Check whether the found version of bash is able to cope with paths in
+        # the host path format. If not, don't return it as it can't be used to
+        # run scripts. For example, WSL's bash.exe requires '/mnt/c/foo' rather
+        # than 'C:\\foo' or 'C:/foo'.
+        if self.isWindows and self.bashPath:
+            command = [self.bashPath, '-c',
+                       '[[ -f "%s" ]]' % self.bashPath.replace('\\', '\\\\')]
+            _, _, exitCode = lit.util.executeCommand(command)
+            if exitCode:
+                self.bashPath = ''
+
         return self.bashPath
 
     def getToolsPath(self, dir, paths, tools):
Index: utils/lit/lit/TestRunner.py
===================================================================
--- utils/lit/lit/TestRunner.py
+++ utils/lit/lit/TestRunner.py
@@ -1073,18 +1073,14 @@
     return out, err, exitCode, timeoutInfo
 
 def executeScript(test, litConfig, tmpBase, commands, cwd):
-    bashPath = litConfig.getBashPath()
-    isWin32CMDEXE = (litConfig.isWindows and not bashPath)
     script = tmpBase + '.script'
-    if isWin32CMDEXE:
+    if litConfig.isWindows:
         script += '.bat'
 
     # Write script file
     mode = 'w'
-    if litConfig.isWindows and not isWin32CMDEXE:
-      mode += 'b'  # Avoid CRLFs when writing bash scripts.
     f = open(script, mode)
-    if isWin32CMDEXE:
+    if litConfig.isWindows:
         for i, ln in enumerate(commands):
             commands[i] = re.sub(kPdbgRegex, "echo '\\1' > nul && ", ln)
         if litConfig.echo_all_commands:
@@ -1103,9 +1099,11 @@
     f.write('\n')
     f.close()
 
-    if isWin32CMDEXE:
+    if litConfig.isWindows:
         command = ['cmd','/c', script]
     else:
+        bashPath = litConfig.getBashPath()
+
         if bashPath:
             command = [bashPath, script]
         else: