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 597712bc1313057daaa4ee32730b46c3951eb78d..4724fabc0d6a72cf57923cea7e6da44d94563052 100644 (file)
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -34,6 +34,7 @@
 #include <time.h>
 #include <assert.h>
 #include <signal.h>
+#include <dlfcn.h>
 #include <urcu/uatomic.h>
 #include <urcu/futex.h>
 #include <urcu/compiler.h>
@@ -51,6 +52,7 @@
 #include "lttng-tracer-core.h"
 #include "compat.h"
 #include "../libringbuffer/tlsfixup.h"
+#include "lttng-ust-baddr.h"
 
 /*
  * Has lttng ust comm constructor been called ?
@@ -106,6 +108,7 @@ struct sock_info {
 
        char wait_shm_path[PATH_MAX];
        char *wait_shm_mmap;
+       int session_enabled;
 };
 
 /* Socket from app (connect) to session daemon (listen) for communication */
@@ -122,6 +125,8 @@ struct sock_info global_apps = {
        .notify_socket = -1,
 
        .wait_shm_path = "/" LTTNG_UST_WAIT_FILENAME,
+
+       .session_enabled = 0,
 };
 
 /* TODO: allow global_apps_sock_path override */
@@ -135,6 +140,8 @@ struct sock_info local_apps = {
 
        .socket = -1,
        .notify_socket = -1,
+
+       .session_enabled = 0,
 };
 
 static int wait_poll_fallback;
@@ -701,6 +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)
 {
@@ -1206,6 +1224,8 @@ restart:
                        ret = handle_message(sock_info, sock, &lum);
                        if (ret) {
                                ERR("Error handling message for %s socket", sock_info->name);
+                       } else {
+                               handle_pending_statedumps(sock_info);
                        }
                        continue;
                default:
@@ -1519,3 +1539,9 @@ void ust_after_fork_child(sigset_t *restore_sigset)
        ust_after_fork_common(restore_sigset);
        lttng_ust_init();
 }
+
+void lttng_ust_sockinfo_session_enabled(void *owner)
+{
+       struct sock_info *sock_info = owner;
+       sock_info->session_enabled = 1;
+}