Fix: liblttng-ust process startup hang when sessiond is stopped

[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 4d437fc58ac14d651825fe71788a1674a4126db1..ae2e518965e94e37a9743e7c022023eb880e206a 100644 (file)
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -625,6 +625,25 @@ void cleanup_sock_info(struct sock_info *sock_info, int exiting)
 {
        int ret;
 
+       if (sock_info->root_handle != -1) {
+               ret = lttng_ust_objd_unref(sock_info->root_handle, 1);
+               if (ret) {
+                       ERR("Error unref root handle");
+               }
+               sock_info->root_handle = -1;
+       }
+       sock_info->constructor_sem_posted = 0;
+
+       /*
+        * wait_shm_mmap, socket and notify socket are used by listener
+        * threads outside of the ust lock, so we cannot tear them down
+        * ourselves, because we cannot join on these threads. Leave
+        * responsibility of cleaning up these resources to the OS
+        * process exit.
+        */
+       if (exiting)
+               return;
+
        if (sock_info->socket != -1) {
                ret = ustcomm_close_unix_sock(sock_info->socket);
                if (ret) {
@@ -639,21 +658,7 @@ void cleanup_sock_info(struct sock_info *sock_info, int exiting)
                }
                sock_info->notify_socket = -1;
        }
-       if (sock_info->root_handle != -1) {
-               ret = lttng_ust_objd_unref(sock_info->root_handle, 1);
-               if (ret) {
-                       ERR("Error unref root handle");
-               }
-               sock_info->root_handle = -1;
-       }
-       sock_info->constructor_sem_posted = 0;
-       /*
-        * wait_shm_mmap is used by listener threads outside of the
-        * ust lock, so we cannot tear it down ourselves, because we
-        * cannot join on these threads. Leave this task to the OS
-        * process exit.
-        */
-       if (!exiting && sock_info->wait_shm_mmap) {
+       if (sock_info->wait_shm_mmap) {
                ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE));
                if (ret) {
                        ERR("Error unmapping wait shm");
@@ -910,11 +915,6 @@ restart:
                has_waited = 1;
                prev_connect_failed = 0;
        }
-       ust_lock();
-
-       if (lttng_ust_comm_should_quit) {
-               goto quit;
-       }
 
        if (sock_info->socket != -1) {
                ret = ustcomm_close_unix_sock(sock_info->socket);
@@ -939,6 +939,13 @@ restart:
                if (ret < 0) {
                        DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name);
                        prev_connect_failed = 1;
+
+                       ust_lock();
+
+                       if (lttng_ust_comm_should_quit) {
+                               goto quit;
+                       }
+
                        /*
                         * If we cannot find the sessiond daemon, don't delay
                         * constructor execution.
@@ -976,6 +983,12 @@ restart:
                WARN("Unsuppoorted timeout value %ld", timeout);
        }
 
+       ust_lock();
+
+       if (lttng_ust_comm_should_quit) {
+               goto quit;
+       }
+
        /*
         * Create only one root handle per listener thread for the whole
         * process lifetime, so we ensure we get ID which is statically