Fix: baddr_statedump deadlock with JUL tracing

[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 b99bf00edec2df760df075f0ad77597a3e1a54d1..4724fabc0d6a72cf57923cea7e6da44d94563052 100644 (file)
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -108,7 +108,7 @@ struct sock_info {
 
        char wait_shm_path[PATH_MAX];
        char *wait_shm_mmap;
-       struct lttng_session *session_enabled;
+       int session_enabled;
 };
 
 /* Socket from app (connect) to session daemon (listen) for communication */
@@ -126,7 +126,7 @@ struct sock_info global_apps = {
 
        .wait_shm_path = "/" LTTNG_UST_WAIT_FILENAME,
 
-       .session_enabled = NULL,
+       .session_enabled = 0,
 };
 
 /* TODO: allow global_apps_sock_path override */
@@ -141,7 +141,7 @@ struct sock_info local_apps = {
        .socket = -1,
        .notify_socket = -1,
 
-       .session_enabled = NULL,
+       .session_enabled = 0,
 };
 
 static int wait_poll_fallback;
@@ -708,6 +708,17 @@ error:
        return ret;
 }
 
+static
+void handle_pending_statedumps(struct sock_info *sock_info)
+{
+       int ctor_passed = sock_info->constructor_sem_posted;
+
+       if (ctor_passed && sock_info->session_enabled) {
+               sock_info->session_enabled = 0;
+               lttng_handle_pending_statedumps(&lttng_ust_baddr_statedump);
+       }
+}
+
 static
 void cleanup_sock_info(struct sock_info *sock_info, int exiting)
 {
@@ -1214,13 +1225,7 @@ restart:
                        if (ret) {
                                ERR("Error handling message for %s socket", sock_info->name);
                        } else {
-                               struct lttng_session *session;
-
-                               session = sock_info->session_enabled;
-                               if (session) {
-                                       sock_info->session_enabled = NULL;
-                                       lttng_ust_baddr_statedump(session);
-                               }
+                               handle_pending_statedumps(sock_info);
                        }
                        continue;
                default:
@@ -1535,9 +1540,8 @@ void ust_after_fork_child(sigset_t *restore_sigset)
        lttng_ust_init();
 }
 
-void lttng_ust_sockinfo_session_enabled(void *owner,
-               struct lttng_session *session_enabled)
+void lttng_ust_sockinfo_session_enabled(void *owner)
 {
        struct sock_info *sock_info = owner;
-       sock_info->session_enabled = session_enabled;
+       sock_info->session_enabled = 1;
 }