Fix: compat poll: add missing empty revents checks

Poll returns the entire array, including entries that have no activity.
We need to check them explicitly.

Fixes #747

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Conflicts:
	src/bin/lttng-sessiond/ht-cleanup.c

diff --git a/src/bin/lttng-consumerd/health-consumerd.c b/src/bin/lttng-consumerd/health-consumerd.c
index d1478e54de9268c778efe13a85bf7a8c843c1b9f..e8afd963f7c058ee1cb258cc7db6def5ea48d76f 100644 (file)
--- a/src/bin/lttng-consumerd/health-consumerd.c
+++ b/src/bin/lttng-consumerd/health-consumerd.c
@@ -260,6 +260,11 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = check_health_quit_pipe(pollfd, revents);
                        if (ret) {

diff --git a/src/bin/lttng-relayd/health-relayd.c b/src/bin/lttng-relayd/health-relayd.c
index 8194c3e4bfba9525c878116da96f2928bec2bc9c..402b44277777b07a7ccd9e49d47e69e1049549d7 100644 (file)
--- a/src/bin/lttng-relayd/health-relayd.c
+++ b/src/bin/lttng-relayd/health-relayd.c
@@ -329,6 +329,11 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = check_health_quit_pipe(pollfd, revents);
                        if (ret) {

diff --git a/src/bin/lttng-relayd/live.c b/src/bin/lttng-relayd/live.c
index 29217b151b582ba297b160fbf75dd2146cafd6b1..2af71c18dfbf1a93b1997a1b1b546481a063eaa0 100644 (file)
--- a/src/bin/lttng-relayd/live.c
+++ b/src/bin/lttng-relayd/live.c
@@ -515,6 +515,11 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
@@ -1948,6 +1953,11 @@ restart:
 
                        health_code_update();
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = check_thread_quit_pipe(pollfd, revents);
                        if (ret) {

diff --git a/src/bin/lttng-relayd/main.c b/src/bin/lttng-relayd/main.c
index 439e81065f228a23aeea0d272ced38d91d7847eb..0f381f7f5e46d7e450d0b54824882865af4ac626 100644 (file)
--- a/src/bin/lttng-relayd/main.c
+++ b/src/bin/lttng-relayd/main.c
@@ -834,6 +834,11 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
@@ -2501,6 +2506,11 @@ restart:
 
                        health_code_update();
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
@@ -2603,46 +2613,49 @@ restart:
 
                        health_code_update();
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Skip the command pipe. It's handled in the first loop. */
                        if (pollfd == relay_conn_pipe[0]) {
                                continue;
                        }
 
-                       if (revents) {
-                               rcu_read_lock();
-                               conn = connection_find_by_sock(relay_connections_ht, pollfd);
-                               if (!conn) {
-                                       /* Skip it. Might be removed before. */
+                       rcu_read_lock();
+                       conn = connection_find_by_sock(relay_connections_ht, pollfd);
+                       if (!conn) {
+                               /* Skip it. Might be removed before. */
+                               rcu_read_unlock();
+                               continue;
+                       }
+
+                       if (revents & LPOLLIN) {
+                               if (conn->type != RELAY_DATA) {
                                        rcu_read_unlock();
                                        continue;
                                }
 
-                               if (revents & LPOLLIN) {
-                                       if (conn->type != RELAY_DATA) {
-                                               rcu_read_unlock();
-                                               continue;
-                                       }
-
-                                       ret = relay_process_data(conn);
-                                       /* Connection closed */
-                                       if (ret < 0) {
-                                               cleanup_connection_pollfd(&events, pollfd);
-                                               destroy_connection(relay_connections_ht, conn);
-                                               DBG("Data connection closed with %d", pollfd);
-                                               /*
-                                                * Every goto restart call sets the last seen fd where
-                                                * here we don't really care since we gracefully
-                                                * continue the loop after the connection is deleted.
-                                                */
-                                       } else {
-                                               /* Keep last seen port. */
-                                               last_seen_data_fd = pollfd;
-                                               rcu_read_unlock();
-                                               goto restart;
-                                       }
+                               ret = relay_process_data(conn);
+                               /* Connection closed */
+                               if (ret < 0) {
+                                       cleanup_connection_pollfd(&events, pollfd);
+                                       destroy_connection(relay_connections_ht, conn);
+                                       DBG("Data connection closed with %d", pollfd);
+                                       /*
+                                        * Every goto restart call sets the last seen fd where
+                                        * here we don't really care since we gracefully
+                                        * continue the loop after the connection is deleted.
+                                        */
+                               } else {
+                                       /* Keep last seen port. */
+                                       last_seen_data_fd = pollfd;
+                                       rcu_read_unlock();
+                                       goto restart;
                                }
-                               rcu_read_unlock();
                        }
+                       rcu_read_unlock();
                }
                last_seen_data_fd = -1;
        }

diff --git a/src/bin/lttng-sessiond/ht-cleanup.c b/src/bin/lttng-sessiond/ht-cleanup.c
index a201506c0eb1da3ad94ac110c351ad3fc0d064e7..f343d620b03e80b5b657ce1970892d34f3d7866b 100644 (file)
--- a/src/bin/lttng-sessiond/ht-cleanup.c
+++ b/src/bin/lttng-sessiond/ht-cleanup.c
@@ -89,6 +89,14 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /*
+                                * No activity for this FD
+                                * (poll implementation).
+                                */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {

diff --git a/src/bin/lttng-sessiond/jul-thread.c b/src/bin/lttng-sessiond/jul-thread.c
index 1630fc55348b983a509432f6fe1d748eb92e683d..d6f07d8693c4fc7de0c9c6859470025e2f50c0be 100644 (file)
--- a/src/bin/lttng-sessiond/jul-thread.c
+++ b/src/bin/lttng-sessiond/jul-thread.c
@@ -307,6 +307,11 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {

diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index e7ca569e90a5d632581632389edab95ca7acce79..cc880bacfc167bac16cbf589092369d335c8881d 100644 (file)
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -1030,6 +1030,11 @@ static void *thread_manage_kernel(void *data)
 
                        health_code_update();
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
@@ -1175,6 +1180,11 @@ restart:
 
                health_code_update();
 
+               if (!revents) {
+                       /* No activity for this FD (poll implementation). */
+                       continue;
+               }
+
                /* Thread quit pipe has been closed. Killing thread. */
                ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                if (ret) {
@@ -1302,6 +1312,11 @@ restart_poll:
 
                        health_code_update();
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /*
                         * Thread quit pipe has been triggered, flag that we should stop
                         * but continue the current loop to handle potential data from
@@ -1478,6 +1493,11 @@ static void *thread_manage_apps(void *data)
 
                        health_code_update();
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
@@ -1656,6 +1676,11 @@ static void sanitize_wait_queue(struct ust_reg_wait_queue *wait_queue)
                uint32_t revents = LTTNG_POLL_GETEV(&events, i);
                int pollfd = LTTNG_POLL_GETFD(&events, i);
 
+               if (!revents) {
+                       /* No activity for this FD (poll implementation). */
+                       continue;
+               }
+
                cds_list_for_each_entry_safe(wait_node, tmp_wait_node,
                                &wait_queue->head, head) {
                        if (pollfd == wait_node->app->sock &&
@@ -1995,6 +2020,11 @@ static void *thread_registration_apps(void *data)
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
@@ -3831,6 +3861,11 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
@@ -4003,6 +4038,11 @@ static void *thread_manage_clients(void *data)
 
                        health_code_update();
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {

diff --git a/src/bin/lttng-sessiond/ust-thread.c b/src/bin/lttng-sessiond/ust-thread.c
index 080afa53a692487d2e7bc12f29ae0bee9c932f72..d0ea32480892a4511685b2ea36ff98ac0f30085b 100644 (file)
--- a/src/bin/lttng-sessiond/ust-thread.c
+++ b/src/bin/lttng-sessiond/ust-thread.c
@@ -91,6 +91,11 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {

diff --git a/src/common/consumer.c b/src/common/consumer.c
index 8bac35e7db8aa492f6f3a3056f5dfa623a8588f6..72c5f3426f0cc4cbfce38d951eff38b0ee188418 100644 (file)
--- a/src/common/consumer.c
+++ b/src/common/consumer.c
@@ -2211,6 +2211,11 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        if (pollfd == lttng_pipe_get_readfd(ctx->consumer_metadata_pipe)) {
                                if (revents & (LPOLLERR | LPOLLHUP )) {
                                        DBG("Metadata thread pipe hung up");
@@ -2781,10 +2786,11 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
-                       /* Just don't waste time if no returned events for the fd */
                        if (!revents) {
+                               /* No activity for this FD (poll implementation). */
                                continue;
                        }
+
                        if (pollfd == ctx->consumer_channel_pipe[0]) {
                                if (revents & (LPOLLERR | LPOLLHUP)) {
                                        DBG("Channel thread pipe hung up");