Fix: add missing rcu lock for UST lookup

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

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 491acde45f760a5613c338a91263231cffffbbc3..456ddeb77d85fd4d1a6f70ca7116494435a12b5e 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -152,6 +152,7 @@ static void list_lttng_channels(int domain, struct ltt_session *session,
                struct lttng_ht_iter iter;
                struct ltt_ust_channel *uchan;
 
+               rcu_read_lock();
                cds_lfht_for_each_entry(session->ust_session->domain_global.channels->ht,
                                &iter.iter, uchan, node.node) {
                        strncpy(channels[i].name, uchan->name, LTTNG_SYMBOL_NAME_LEN);
@@ -171,6 +172,7 @@ static void list_lttng_channels(int domain, struct ltt_session *session,
                        }
                        i++;
                }
+               rcu_read_unlock();
                break;
        }
        default:
@@ -433,6 +435,8 @@ static int init_kernel_tracing(struct ltt_kernel_session *session)
 
        assert(session);
 
+       rcu_read_lock();
+
        if (session->consumer_fds_sent == 0 && session->consumer != NULL) {
                cds_lfht_for_each_entry(session->consumer->socks->ht, &iter.iter,
                                socket, node.node) {
@@ -450,6 +454,7 @@ static int init_kernel_tracing(struct ltt_kernel_session *session)
        }
 
 error:
+       rcu_read_unlock();
        return ret;
 }
 
@@ -643,6 +648,8 @@ static int setup_relayd(struct ltt_session *session)
 
        DBG2("Setting relayd for session %s", session->name);
 
+       rcu_read_lock();
+
        if (usess && usess->consumer && usess->consumer->type == CONSUMER_DST_NET
                        && usess->consumer->enabled) {
                /* For each consumer socket, send relayd sockets */
@@ -679,6 +686,7 @@ static int setup_relayd(struct ltt_session *session)
        }
 
 error:
+       rcu_read_unlock();
        return ret;
 }
 
@@ -758,6 +766,8 @@ int cmd_disable_channel(struct ltt_session *session, int domain,
 
        usess = session->ust_session;
 
+       rcu_read_lock();
+
        switch (domain) {
        case LTTNG_DOMAIN_KERNEL:
        {
@@ -802,6 +812,7 @@ int cmd_disable_channel(struct ltt_session *session, int domain,
        ret = LTTNG_OK;
 
 error:
+       rcu_read_unlock();
        return ret;
 }
 
@@ -822,6 +833,8 @@ int cmd_enable_channel(struct ltt_session *session,
 
        DBG("Enabling channel %s for session %s", attr->name, session->name);
 
+       rcu_read_lock();
+
        switch (domain) {
        case LTTNG_DOMAIN_KERNEL:
        {
@@ -890,6 +903,7 @@ int cmd_enable_channel(struct ltt_session *session,
        }
 
 error:
+       rcu_read_unlock();
        return ret;
 }
 
@@ -902,6 +916,8 @@ int cmd_disable_event(struct ltt_session *session, int domain,
 {
        int ret;
 
+       rcu_read_lock();
+
        switch (domain) {
        case LTTNG_DOMAIN_KERNEL:
        {
@@ -916,7 +932,7 @@ int cmd_disable_event(struct ltt_session *session, int domain,
                        goto error;
                }
 
-               ret = event_kernel_disable_tracepoint(ksess, kchan, event_name);
+               ret = event_kernel_disable_tracepoint(kchan, event_name);
                if (ret != LTTNG_OK) {
                        goto error;
                }
@@ -960,6 +976,7 @@ int cmd_disable_event(struct ltt_session *session, int domain,
        ret = LTTNG_OK;
 
 error:
+       rcu_read_unlock();
        return ret;
 }
 
@@ -971,6 +988,8 @@ int cmd_disable_event_all(struct ltt_session *session, int domain,
 {
        int ret;
 
+       rcu_read_lock();
+
        switch (domain) {
        case LTTNG_DOMAIN_KERNEL:
        {
@@ -985,7 +1004,7 @@ int cmd_disable_event_all(struct ltt_session *session, int domain,
                        goto error;
                }
 
-               ret = event_kernel_disable_all(ksess, kchan);
+               ret = event_kernel_disable_all(kchan);
                if (ret != LTTNG_OK) {
                        goto error;
                }
@@ -1029,6 +1048,7 @@ int cmd_disable_event_all(struct ltt_session *session, int domain,
        ret = LTTNG_OK;
 
 error:
+       rcu_read_unlock();
        return ret;
 }
 
@@ -1111,13 +1131,15 @@ int cmd_enable_event(struct ltt_session *session, int domain,
                char *channel_name, struct lttng_event *event,
                struct lttng_filter_bytecode *filter, int wpipe)
 {
-       int ret;
+       int ret, channel_created = 0;
        struct lttng_channel *attr;
 
        assert(session);
        assert(event);
        assert(channel_name);
 
+       rcu_read_lock();
+
        switch (domain) {
        case LTTNG_DOMAIN_KERNEL:
        {
@@ -1139,6 +1161,8 @@ int cmd_enable_event(struct ltt_session *session, int domain,
                                goto error;
                        }
                        free(attr);
+
+                       channel_created = 1;
                }
 
                /* Get the newly created kernel channel pointer */
@@ -1150,9 +1174,12 @@ int cmd_enable_event(struct ltt_session *session, int domain,
                        goto error;
                }
 
-               ret = event_kernel_enable_tracepoint(session->kernel_session, kchan,
-                               event);
+               ret = event_kernel_enable_tracepoint(kchan, event);
                if (ret != LTTNG_OK) {
+                       if (channel_created) {
+                               /* Let's not leak a useless channel. */
+                               kernel_destroy_channel(kchan);
+                       }
                        goto error;
                }
 
@@ -1211,6 +1238,7 @@ int cmd_enable_event(struct ltt_session *session, int domain,
        ret = LTTNG_OK;
 
 error:
+       rcu_read_unlock();
        return ret;
 }
 
@@ -1227,6 +1255,8 @@ int cmd_enable_event_all(struct ltt_session *session, int domain,
        assert(session);
        assert(channel_name);
 
+       rcu_read_lock();
+
        switch (domain) {
        case LTTNG_DOMAIN_KERNEL:
        {
@@ -1260,21 +1290,18 @@ int cmd_enable_event_all(struct ltt_session *session, int domain,
 
                switch (event_type) {
                case LTTNG_EVENT_SYSCALL:
-                       ret = event_kernel_enable_all_syscalls(session->kernel_session,
-                                       kchan, kernel_tracer_fd);
+                       ret = event_kernel_enable_all_syscalls(kchan, kernel_tracer_fd);
                        break;
                case LTTNG_EVENT_TRACEPOINT:
                        /*
                         * This call enables all LTTNG_KERNEL_TRACEPOINTS and
                         * events already registered to the channel.
                         */
-                       ret = event_kernel_enable_all_tracepoints(session->kernel_session,
-                                       kchan, kernel_tracer_fd);
+                       ret = event_kernel_enable_all_tracepoints(kchan, kernel_tracer_fd);
                        break;
                case LTTNG_EVENT_ALL:
                        /* Enable syscalls and tracepoints */
-                       ret = event_kernel_enable_all(session->kernel_session,
-                                       kchan, kernel_tracer_fd);
+                       ret = event_kernel_enable_all(kchan, kernel_tracer_fd);
                        break;
                default:
                        ret = LTTNG_ERR_KERN_ENABLE_FAIL;
@@ -1283,6 +1310,10 @@ int cmd_enable_event_all(struct ltt_session *session, int domain,
 
                /* Manage return value */
                if (ret != LTTNG_OK) {
+                       /*
+                        * On error, cmd_enable_channel call will take care of destroying
+                        * the created channel if it was needed.
+                        */
                        goto error;
                }
 
@@ -1357,6 +1388,7 @@ int cmd_enable_event_all(struct ltt_session *session, int domain,
        ret = LTTNG_OK;
 
 error:
+       rcu_read_unlock();
        return ret;
 }