Fix missing events for all threads pollfd struct

The thread_quit_pipe event field of the pollfd was not set nor zeroed.
At high rate UST registration and modifying the pollfd set frequently,
the session daemon hang on the poll() call even if the thread_quit_pipe
was closed and explain by poll() "undefined behavior".

Also add a MSG() and ERR() statement after some errors.

Signed-off-by: David Goulet <david.goulet@polymtl.ca>

diff --git a/ltt-sessiond/main.c b/ltt-sessiond/main.c
index 436ee9f167e8a45853fe9b58557555de74b82629..d61cd7bc512f3c7dbb682950e55ff448db0507f4 100644 (file)
--- a/ltt-sessiond/main.c
+++ b/ltt-sessiond/main.c
@@ -567,6 +567,8 @@ static int update_kernel_pollfd(void)
 
        /* Adding the quit pipe */
        kernel_pollfd[nb_fd - 1].fd = thread_quit_pipe[0];
+       kernel_pollfd[nb_fd - 1].events =
+               POLLHUP | POLLNVAL | POLLERR | POLLIN | POLLRDHUP | POLLPRI;
 
        return nb_fd;
 
@@ -667,6 +669,8 @@ static void *thread_manage_kernel(void *data)
                        goto error;
                } else if (ret == 0) {
                        /* Should not happen since timeout is infinite */
+                       ERR("Return value of poll is 0 with an infinite timeout.\n"
+                               "This should not have happened! Continuing...");
                        continue;
                }
 
@@ -860,6 +864,9 @@ static int update_apps_cmd_pollfd(unsigned int nb_fd, unsigned int old_nb_fd,
 
        /* First fd is always the quit pipe */
        (*pollfd)[0].fd = thread_quit_pipe[0];
+       (*pollfd)[0].events =
+               POLLHUP | POLLNVAL | POLLERR | POLLIN | POLLRDHUP | POLLPRI;
+
        /* Apps command pipe */
        (*pollfd)[1].fd = apps_cmd_pipe[0];
        (*pollfd)[1].events = POLLIN;
@@ -887,6 +894,7 @@ static int update_apps_cmd_pollfd(unsigned int nb_fd, unsigned int old_nb_fd,
                 * best which are the thread_quit_pipe and apps_cmd_pipe.
                 */
                nb_fd = 2;
+               MSG("nb_fd < 2 --> Not good! Continuing...");
        }
 
        /* Destroy old pollfd */
@@ -1105,6 +1113,8 @@ static void *thread_registration_apps(void *data)
 
        /* First fd is always the quit pipe */
        pollfd[0].fd = thread_quit_pipe[0];
+       pollfd[0].events =
+               POLLHUP | POLLNVAL | POLLERR | POLLIN | POLLRDHUP | POLLPRI;
 
        /* Apps socket */
        pollfd[1].fd = apps_sock;
@@ -2619,6 +2629,8 @@ static void *thread_manage_clients(void *data)
 
        /* First fd is always the quit pipe */
        pollfd[0].fd = thread_quit_pipe[0];
+       pollfd[0].events =
+               POLLHUP | POLLNVAL | POLLERR | POLLIN | POLLRDHUP | POLLPRI;
 
        /* Apps socket */
        pollfd[1].fd = client_sock;