ipcpd: Fix shutdown of link-state routing

The link_state component tried to unregister from the notifier while
it had threads running.

The deadlock happens when notifier_event had a rdlock trying to delete
a neighbour, while notifier_unreg tries to take the write lock. And
the delete can't complete in the notifier.

https://tree.taiga.io/project/dstaesse-ouroboros/us/113

We need to make sure that all threads are stopped before unregistering
from the notifier.

Updated link_state to use the start/stop() paradigm and not
create/cancel threads within init/fini().

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/ipcpd/unicast/dt.c b/src/ipcpd/unicast/dt.c
index 39b0025f..38cee75d 100644
--- a/src/ipcpd/unicast/dt.c
+++ b/src/ipcpd/unicast/dt.c
@@ -726,8 +726,16 @@ int dt_start(void)
                 goto fail_listener;
         }
 
+        if (routing_start() < 0) {
+                log_err("Failed to start routing.");
+                goto fail_routing;
+        }
+
         return 0;
 
+ fail_routing:
+        pthread_cancel(dt.listener);
+        pthread_join(dt.listener, NULL);
  fail_listener:
         notifier_unreg(&handle_event);
  fail_notifier_reg:
@@ -738,6 +746,8 @@ int dt_start(void)
 
 void dt_stop(void)
 {
+        routing_stop();
+
         pthread_cancel(dt.listener);
         pthread_join(dt.listener, NULL);