Fix: check for removal of session's shm_path in destroy()

[lttng-tools.git] / src / bin / lttng-sessiond / main.c

diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index f9b41d2707bd26aff4f95a72aa1885d2f2f09280..5e644a72d9f821ec638d31e752542fa42cf2cffb 100644 (file)
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -366,10 +366,21 @@ LTTNG_HIDDEN
 void sessiond_notify_ready(void)
 {
        /*
-        * The _return variant is used since the implied memory barriers are
-        * required.
+        * This memory barrier is paired with the one performed by
+        * the client thread after it has seen that 'lttng_sessiond_ready' is 0.
+        *
+        * The purpose of these memory barriers is to ensure that all
+        * initialization operations of the various threads that call this
+        * function to signal that they are ready are commited/published
+        * before the client thread can see the 'lttng_sessiond_ready' counter
+        * reach 0.
+        *
+        * Note that this could be a 'write' memory barrier, but a full barrier
+        * is used in case the code using this utility changes. The performance
+        * implications of this choice are minimal since this is a slow path.
         */
-       (void) uatomic_sub_return(&lttng_sessiond_ready, 1);
+       cmm_smp_mb();
+       uatomic_sub(&lttng_sessiond_ready, 1);
 }
 
 static
@@ -847,7 +858,7 @@ error:
  *
  * Useful for CPU hotplug feature.
  */
-static int update_kernel_stream(struct consumer_data *consumer_data, int fd)
+static int update_kernel_stream(int fd)
 {
        int ret = 0;
        struct ltt_session *session;
@@ -1081,7 +1092,7 @@ static void *thread_manage_kernel(void *data)
                                         * New CPU detected by the kernel. Adding kernel stream to
                                         * kernel session and updating the kernel consumer
                                         */
-                                       ret = update_kernel_stream(&kconsumer_data, pollfd);
+                                       ret = update_kernel_stream(pollfd);
                                        if (ret < 0) {
                                                continue;
                                        }
@@ -4563,8 +4574,17 @@ static void *thread_manage_clients(void *data)
                if (ret > 0 || (ret < 0 && errno != EINTR)) {
                        goto exit;
                }
-               cmm_smp_rmb();
        }
+       /*
+        * This barrier is paired with the one in sessiond_notify_ready() to
+        * ensure that loads accessing data initialized by the other threads,
+        * on which this thread was waiting, are not performed before this point.
+        *
+        * Note that this could be a 'read' memory barrier, but a full barrier
+        * is used in case the code changes. The performance implications of
+        * this choice are minimal since this is a slow path.
+        */
+       cmm_smp_mb();
 
        /* This testpoint is after we signal readiness to the parent. */
        if (testpoint(sessiond_thread_manage_clients)) {
@@ -4578,6 +4598,8 @@ static void *thread_manage_clients(void *data)
        health_code_update();
 
        while (1) {
+               const struct cmd_completion_handler *cmd_completion_handler;
+
                DBG("Accepting client command ...");
 
                /* Inifinite blocking call, waiting for transmission */
@@ -4720,6 +4742,18 @@ static void *thread_manage_clients(void *data)
                        continue;
                }
 
+               cmd_completion_handler = cmd_pop_completion_handler();
+               if (cmd_completion_handler) {
+                       enum lttng_error_code completion_code;
+
+                       completion_code = cmd_completion_handler->run(
+                                       cmd_completion_handler->data);
+                       if (completion_code != LTTNG_OK) {
+                               clean_command_ctx(&cmd_ctx);
+                               continue;
+                       }
+               }
+
                health_code_update();
 
                DBG("Sending response (size: %d, retcode: %s (%d))",
@@ -5810,6 +5844,12 @@ int main(int argc, char **argv)
                goto exit_set_signal_handler;
        }
 
+       /*
+        * Init config from environment variables.
+        * Command line option override env configuration per-doc. Do env first.
+        */
+       sessiond_config_apply_env_config(&config);
+
        /*
         * Parse arguments and load the daemon configuration file.
         *
@@ -5824,9 +5864,6 @@ int main(int argc, char **argv)
                goto exit_options;
        }
 
-       /* Init config from environment variables. */
-       sessiond_config_apply_env_config(&config);
-
        /*
         * Resolve all paths received as arguments, configuration option, or
         * through environment variable as absolute paths. This is necessary