[PATCH] Add timeout to _poll_loop function to avoid infinite looping

[Jiri Prochazka]

When Slave is using NetworkManager, polling is used to activate DBus connection.
This may result in infinite loop (eg. when device is not in LOWER_UP state, but is in UP state).
This patch adds timeout control in _poll_loop method, timeout value is set to 10s.

Signed-off-by: Jiri Prochazka 
---
 lnst/Slave/NmConfigDevice.py | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/lnst/Slave/NmConfigDevice.py b/lnst/Slave/NmConfigDevice.py
index 8e2f1dd..c884d70 100644
--- a/lnst/Slave/NmConfigDevice.py
+++ b/lnst/Slave/NmConfigDevice.py
@@ -28,6 +28,7 @@ from lnst.Common.Config import lnst_config
 NM_BUS = "org.freedesktop.NetworkManager"
 OBJ_PRE = "/org/freedesktop/NetworkManager"
 IF_PRE = NM_BUS
+POLL_LOOP_TIMEOUT = 10

#NetworkManager constants for state values
 _ACON_ACTIVATED = 2
@@ -152,11 +153,15 @@ class NmConfigDeviceGeneric(object):
         if self._device_state == self._wait_for:
             self._loop.quit()

-    def _poll_loop(self, func, expected_val, *args):
-        while True:
+    def _poll_loop(self, func, expected_val, timeout, *args):
+        timer = 0
+        while timer < timeout:
             if func(*args) == expected_val:
-                break
+                return
             time.sleep(1)
+            timer += 1
+        msg = "Timed out during NetworkManager polling."
+        raise Exception(msg)

def _convert_hwaddr(self, dev_config):
         if "hwaddr" in dev_config:
@@ -276,6 +281,7 @@ class NmConfigDeviceGeneric(object):
                                            "org.freedesktop.DBus.Properties")
             self._poll_loop(act_con_props.Get,
                             _ACON_ACTIVATED,
+                            POLL_LOOP_TIMEOUT,
                             IF_PRE + ".Connection.Active", "State")

def _nm_deactivate_connection(self):
@@ -341,6 +347,7 @@ class NmConfigDeviceEth(NmConfigDeviceGeneric):

self._poll_loop(dev_props.Get,
                             _DEV_DISCONNECTED,
+                            POLL_LOOP_TIMEOUT,
                             IF_PRE + ".Device", "State")
         else:
             exec_cmd("ip link set %s up" % config["name"])

[Ondrej Lichtner]

On Mon, Jun 29, 2015 at 04:45:14PM +0200, Jiri Prochazka wrote:
> When Slave is using NetworkManager, polling is used to activate DBus connection.
> This may result in infinite loop (eg. when device is not in LOWER_UP state, but is in UP state).
> This patch adds timeout control in _poll_loop method, timeout value is set to 10s.
>
> Signed-off-by: Jiri Prochazka

Acked-by: Ondrej Lichtner

[Jan Tluka]

Mon, Jun 29, 2015 at 04:45:14PM CEST, [e-mail] wrote:
> When Slave is using NetworkManager, polling is used to activate DBus connection.
> This may result in infinite loop (eg. when device is not in LOWER_UP state, but is in UP state).
> This patch adds timeout control in _poll_loop method, timeout value is set to 10s.
>
> Signed-off-by: Jiri Prochazka

applied, thanks.