fix: Handle sys_futex with async cancel, add missing pthread_join

[lttng-ust.git] / liblttng-ust / lttng-ust-comm.c

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index d0641c5c6e510b01d0538d9c36b07c5c430644c6..f41863628c9a097d8394eaa35a2ce2e834ee4e12 100644 (file)
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -578,7 +578,7 @@ error:
 static
 void wait_for_sessiond(struct sock_info *sock_info)
 {
-       int ret;
+       int ret, oldtype;
 
        ust_lock();
        if (lttng_ust_comm_should_quit) {
@@ -595,6 +595,14 @@ void wait_for_sessiond(struct sock_info *sock_info)
        ust_unlock();
 
        DBG("Waiting for %s apps sessiond", sock_info->name);
+       /*
+        * sys_futex does not honor pthread cancel requests. Set to
+        * async.
+        */
+       ret = pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldtype);
+       if (ret) {
+               ERR("Error setting thread cancel type");
+       }
        /* Wait for futex wakeup */
        if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) {
                ret = futex_async((int32_t *) sock_info->wait_shm_mmap,
@@ -613,6 +621,10 @@ void wait_for_sessiond(struct sock_info *sock_info)
                        }
                }
        }
+       ret = pthread_setcanceltype(oldtype, &oldtype);
+       if (ret) {
+               ERR("Error setting thread cancel type");
+       }
        return;
 
 quit:
@@ -913,6 +925,7 @@ void __attribute__((destructor)) lttng_ust_exit(void)
        lttng_ust_comm_should_quit = 1;
        ust_unlock();
 
+       /* cancel threads */
        ret = pthread_cancel(global_apps.ust_listener);
        if (ret) {
                ERR("Error cancelling global ust listener thread");
@@ -923,6 +936,17 @@ void __attribute__((destructor)) lttng_ust_exit(void)
                        ERR("Error cancelling local ust listener thread");
                }
        }
+       /* join threads */
+       ret = pthread_join(global_apps.ust_listener, NULL);
+       if (ret) {
+               ERR("Error joining global ust listener thread");
+       }
+       if (local_apps.allowed) {
+               ret = pthread_join(local_apps.ust_listener, NULL);
+               if (ret) {
+                       ERR("Error joining local ust listener thread");
+               }
+       }
        lttng_ust_cleanup(1);
 }