Only in fail2ban-0.9.3/: ChangeLog.orig
diff -ur fail2ban-0.9.3.orig/fail2ban/server/action.py fail2ban-0.9.3/fail2ban/server/action.py
--- fail2ban-0.9.3.orig/fail2ban/server/action.py	2015-08-01 03:32:13.000000000 +0200
+++ fail2ban-0.9.3/fail2ban/server/action.py	2015-09-23 11:54:38.066927465 +0200
@@ -560,32 +560,33 @@
 			return True
 
 		_cmd_lock.acquire()
-		try: # Try wrapped within another try needed for python version < 2.5
+		try:
+			retcode = None  # to guarantee being defined upon early except
 			stdout = tempfile.TemporaryFile(suffix=".stdout", prefix="fai2ban_")
 			stderr = tempfile.TemporaryFile(suffix=".stderr", prefix="fai2ban_")
-			try:
-				popen = subprocess.Popen(
-					realCmd, stdout=stdout, stderr=stderr, shell=True,
-					preexec_fn=os.setsid  # so that killpg does not kill our process
-				)
-				stime = time.time()
+
+			popen = subprocess.Popen(
+				realCmd, stdout=stdout, stderr=stderr, shell=True,
+				preexec_fn=os.setsid  # so that killpg does not kill our process
+			)
+			stime = time.time()
+			retcode = popen.poll()
+			while time.time() - stime <= timeout and retcode is None:
+				time.sleep(0.1)
 				retcode = popen.poll()
-				while time.time() - stime <= timeout and retcode is None:
-					time.sleep(0.1)
-					retcode = popen.poll()
-				if retcode is None:
-					logSys.error("%s -- timed out after %i seconds." %
-						(realCmd, timeout))
-					pgid = os.getpgid(popen.pid)
-					os.killpg(pgid, signal.SIGTERM)  # Terminate the process
+			if retcode is None:
+				logSys.error("%s -- timed out after %i seconds." %
+				    (realCmd, timeout))
+				pgid = os.getpgid(popen.pid)
+				os.killpg(pgid, signal.SIGTERM)  # Terminate the process
+				time.sleep(0.1)
+				retcode = popen.poll()
+				if retcode is None:  # Still going...
+					os.killpg(pgid, signal.SIGKILL)  # Kill the process
 					time.sleep(0.1)
 					retcode = popen.poll()
-					if retcode is None: # Still going...
-						os.killpg(pgid, signal.SIGKILL)  # Kill the process
-						time.sleep(0.1)
-						retcode = popen.poll()
-			except OSError, e:
-				logSys.error("%s -- failed with %s" % (realCmd, e))
+		except OSError as e:
+			logSys.error("%s -- failed with %s" % (realCmd, e))
 		finally:
 			_cmd_lock.release()
 
@@ -603,15 +604,16 @@
 			return True
 		elif retcode is None:
 			logSys.error("%s -- unable to kill PID %i" % (realCmd, popen.pid))
-		elif retcode < 0:
-			logSys.error("%s -- killed with %s" %
-				(realCmd, signame.get(-retcode, "signal %i" % -retcode)))
+		elif retcode < 0 or retcode > 128:
+			# dash would return negative while bash 128 + n
+			sigcode = -retcode if retcode < 0 else retcode - 128
+			logSys.error("%s -- killed with %s (return code: %s)" %
+				(realCmd, signame.get(sigcode, "signal %i" % sigcode), retcode))
 		else:
 			msg = _RETCODE_HINTS.get(retcode, None)
 			logSys.error("%s -- returned %i" % (realCmd, retcode))
 			if msg:
 				logSys.info("HINT on %i: %s"
 							% (retcode, msg % locals()))
-			return False
-		raise RuntimeError("Command execution failed: %s" % realCmd)
+		return False
 
diff -ur fail2ban-0.9.3.orig/fail2ban/tests/actiontestcase.py fail2ban-0.9.3/fail2ban/tests/actiontestcase.py
--- fail2ban-0.9.3.orig/fail2ban/tests/actiontestcase.py	2015-08-01 03:32:13.000000000 +0200
+++ fail2ban-0.9.3/fail2ban/tests/actiontestcase.py	2015-09-23 11:54:38.074927626 +0200
@@ -196,11 +196,10 @@
 	def testExecuteTimeout(self):
 		stime = time.time()
 		# Should take a minute
-		self.assertRaises(
-			RuntimeError, CommandAction.executeCmd, 'sleep 60', timeout=2)
+		self.assertFalse(CommandAction.executeCmd('sleep 60', timeout=2))
 		# give a test still 1 second, because system could be too busy
 		self.assertTrue(time.time() >= stime + 2 and time.time() <= stime + 3)
-		self.assertTrue(self._is_logged('sleep 60 -- timed out after 2 seconds') 
+		self.assertTrue(self._is_logged('sleep 60 -- timed out after 2 seconds')
 			or self._is_logged('sleep 60 -- timed out after 3 seconds'))
 		self.assertTrue(self._is_logged('sleep 60 -- killed with SIGTERM'))
 
@@ -222,17 +221,16 @@
 				return int(f.read())
 
 		# First test if can kill the bastard
-		self.assertRaises(
-			RuntimeError, CommandAction.executeCmd, 'bash %s' % tmpFilename, timeout=.1)
+		self.assertFalse(CommandAction.executeCmd(
+		                 'bash %s' % tmpFilename, timeout=.1))
 		# Verify that the proccess itself got killed
 		self.assertFalse(pid_exists(getnastypid()))  # process should have been killed
 		self.assertTrue(self._is_logged('timed out'))
 		self.assertTrue(self._is_logged('killed with SIGTERM'))
 
 		# A bit evolved case even though, previous test already tests killing children processes
-		self.assertRaises(
-			RuntimeError, CommandAction.executeCmd, 'out=`bash %s`; echo ALRIGHT' % tmpFilename,
-			timeout=.2)
+		self.assertFalse(CommandAction.executeCmd(
+			'out=`bash %s`; echo ALRIGHT' % tmpFilename, timeout=.2))
 		# Verify that the proccess itself got killed
 		self.assertFalse(pid_exists(getnastypid()))
 		self.assertTrue(self._is_logged('timed out'))