Fix: LPOLLHUP and LPOLLERR when there is still data in pipe/socket

[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 0e7de6e5e4786d27383eec0481a48504a84b5c04..13bd649180452ad8346f8d7a5729446a9c58b157 100644 (file)
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -1165,31 +1165,33 @@ static void *thread_manage_kernel(void *data)
                        }
 
                        /* Check for data on kernel pipe */
-                       if (pollfd == kernel_poll_pipe[0] && (revents & LPOLLIN)) {
-                               (void) lttng_read(kernel_poll_pipe[0],
-                                       &tmp, 1);
-                               /*
-                                * Ret value is useless here, if this pipe gets any actions an
-                                * update is required anyway.
-                                */
-                               update_poll_flag = 1;
-                               continue;
-                       } else {
-                               /*
-                                * New CPU detected by the kernel. Adding kernel stream to
-                                * kernel session and updating the kernel consumer
-                                */
-                               if (revents & LPOLLIN) {
+                       if (revents & LPOLLIN) {
+                               if (pollfd == kernel_poll_pipe[0]) {
+                                       (void) lttng_read(kernel_poll_pipe[0],
+                                               &tmp, 1);
+                                       /*
+                                        * Ret value is useless here, if this pipe gets any actions an
+                                        * update is required anyway.
+                                        */
+                                       update_poll_flag = 1;
+                                       continue;
+                               } else {
+                                       /*
+                                        * New CPU detected by the kernel. Adding kernel stream to
+                                        * kernel session and updating the kernel consumer
+                                        */
                                        ret = update_kernel_stream(&kconsumer_data, pollfd);
                                        if (ret < 0) {
                                                continue;
                                        }
                                        break;
-                                       /*
-                                        * TODO: We might want to handle the LPOLLERR | LPOLLHUP
-                                        * and unregister kernel stream at this point.
-                                        */
                                }
+                       } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                               update_poll_flag = 1;
+                               continue;
+                       } else {
+                               ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                               goto error;
                        }
                }
        }
@@ -1319,9 +1321,14 @@ restart:
 
                /* Event on the registration socket */
                if (pollfd == consumer_data->err_sock) {
-                       if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                       if (revents & LPOLLIN) {
+                               continue;
+                       } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
                                ERR("consumer err socket poll error");
                                goto error;
+                       } else {
+                               ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                               goto error;
                        }
                }
        }
@@ -1451,7 +1458,8 @@ restart_poll:
 
                        if (pollfd == sock) {
                                /* Event on the consumerd socket */
-                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)
+                                               && !(revents & LPOLLIN)) {
                                        ERR("consumer err socket second poll error");
                                        goto error;
                                }
@@ -1469,6 +1477,11 @@ restart_poll:
 
                                goto exit;
                        } else if (pollfd == consumer_data->metadata_fd) {
+                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)
+                                               && !(revents & LPOLLIN)) {
+                                       ERR("consumer err metadata socket second poll error");
+                                       goto error;
+                               }
                                /* UST metadata requests */
                                ret = ust_consumer_metadata_request(
                                                &consumer_data->metadata_sock);
@@ -1636,10 +1649,7 @@ static void *thread_manage_apps(void *data)
 
                        /* Inspect the apps cmd pipe */
                        if (pollfd == apps_cmd_pipe[0]) {
-                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
-                                       ERR("Apps command pipe error");
-                                       goto error;
-                               } else if (revents & LPOLLIN) {
+                               if (revents & LPOLLIN) {
                                        int sock;
 
                                        /* Empty pipe */
@@ -1652,9 +1662,8 @@ static void *thread_manage_apps(void *data)
                                        health_code_update();
 
                                        /*
-                                        * We only monitor the error events of the socket. This
-                                        * thread does not handle any incoming data from UST
-                                        * (POLLIN).
+                                        * Since this is a command socket (write then read),
+                                        * we only monitor the error events of the socket.
                                         */
                                        ret = lttng_poll_add(&events, sock,
                                                        LPOLLERR | LPOLLHUP | LPOLLRDHUP);
@@ -1663,6 +1672,12 @@ static void *thread_manage_apps(void *data)
                                        }
 
                                        DBG("Apps with sock %d added to poll set", sock);
+                               } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                                       ERR("Apps command pipe error");
+                                       goto error;
+                               } else {
+                                       ERR("Unknown poll events %u for sock %d", revents, pollfd);
+                                       goto error;
                                }
                        } else {
                                /*
@@ -1678,6 +1693,9 @@ static void *thread_manage_apps(void *data)
 
                                        /* Socket closed on remote end. */
                                        ust_app_unregister(pollfd);
+                               } else {
+                                       ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                                       goto error;
                                }
                        }
 
@@ -1825,6 +1843,9 @@ static void sanitize_wait_queue(struct ust_reg_wait_queue *wait_queue)
                                 */
                                wait_node = NULL;
                                break;
+                       } else {
+                               ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                               goto error;
                        }
                }
        }
@@ -2185,10 +2206,7 @@ static void *thread_registration_apps(void *data)
 
                        /* Event on the registration socket */
                        if (pollfd == apps_sock) {
-                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
-                                       ERR("Register apps socket poll error");
-                                       goto error;
-                               } else if (revents & LPOLLIN) {
+                               if (revents & LPOLLIN) {
                                        sock = lttcomm_accept_unix_sock(apps_sock);
                                        if (sock < 0) {
                                                goto error;
@@ -2275,6 +2293,12 @@ static void *thread_registration_apps(void *data)
                                         * barrier with the exchange in cds_wfcq_enqueue.
                                         */
                                        futex_nto1_wake(&ust_cmd_queue.futex);
+                               } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                                       ERR("Register apps socket poll error");
+                                       goto error;
+                               } else {
+                                       ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                                       goto error;
                                }
                        }
                }
@@ -4177,9 +4201,14 @@ restart:
 
                        /* Event on the registration socket */
                        if (pollfd == sock) {
-                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                               if (revents & LPOLLIN) {
+                                       continue;
+                               } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
                                        ERR("Health socket poll error");
                                        goto error;
+                               } else {
+                                       ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                                       goto error;
                                }
                        }
                }
@@ -4354,9 +4383,14 @@ static void *thread_manage_clients(void *data)
 
                        /* Event on the registration socket */
                        if (pollfd == client_sock) {
-                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                               if (revents & LPOLLIN) {
+                                       continue;
+                               } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
                                        ERR("Client socket poll error");
                                        goto error;
+                               } else {
+                                       ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                                       goto error;
                                }
                        }
                }