AST-2017-013: chan_skinny: Call pthread_detach when sess threads end

chan_skinny creates a new thread for each new session.  In trying
to be a good cleanup citizen, the threads are joinable and the
unload_module function does a pthread_cancel() and a pthread_join()
on any sessions that are active at that time.  This has an
unintended side effect though. Since you can call pthread_join on a
thread that's already terminated, pthreads keeps the thread's
storage around until you explicitly call pthread_join (or
pthread_detach()).   Since only the module_unload function was
calling pthread_join, and even then only on the ones active at the
tme, the storage for every thread/session ever created sticks
around until asterisk exits.

* A thread can detach itself so the session_destroy() function
  now calls pthread_detach() just before it frees the session
  memory allocation.  The module_unload function still takes care
  of the ones that are still active should the module be unloaded.

ASTERISK-27452
Reported by: Juan Sacco

Change-Id: I9af7268eba14bf76960566f891320f97b974e6dd

diff --git a/channels/chan_skinny.c b/channels/chan_skinny.c
index 6848579258e255b513ddee96b5e55efe28a087f5..b120c79cc82bd01cbdabe58c6a362bea32851430 100644 (file)
--- a/channels/chan_skinny.c
+++ b/channels/chan_skinny.c
@@ -7428,6 +7428,11 @@ static void destroy_session(struct skinnysession *s)
        }
        ast_mutex_unlock(&s->lock);
        ast_mutex_destroy(&s->lock);
+
+       if (s->t != AST_PTHREADT_NULL) {
+               pthread_detach(s->t);
+       }
+
        ast_free(s);
 }
 
@@ -7514,11 +7519,6 @@ static void *skinny_session(void *data)
        int eventmessage = 0;
        struct pollfd fds[1];
 
-       if (!s) {
-               ast_log(LOG_WARNING, "Bad Skinny Session\n");
-               return 0;
-       }
-
        ast_log(LOG_NOTICE, "Starting Skinny session from %s\n", ast_inet_ntoa(s->sin.sin_addr));
 
        pthread_cleanup_push(skinny_session_cleanup, s);
@@ -7684,6 +7684,7 @@ static void *accept_thread(void *ignore)
                s->keepalive_timeout_sched = -1;
 
                if (ast_pthread_create(&s->t, NULL, skinny_session, s)) {
+                       s->t = AST_PTHREADT_NULL;
                        destroy_session(s);
                }
        }