Fix: RCU lock imbalance on error in cmd_snapshot_list_outputs()

[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 c74da94f4cc8ab8ebcbdcccb91fe72f37a125615..86c3c765c8dfb2173137894a4fceffb156515ce9 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -3352,14 +3352,14 @@ ssize_t cmd_snapshot_list_outputs(struct ltt_session *session,
                if (lttng_strncpy(list[idx].name, output->name,
                                sizeof(list[idx].name))) {
                        ret = -LTTNG_ERR_INVALID;
-                       goto error;
+                       goto error_unlock;
                }
                if (output->consumer->type == CONSUMER_DST_LOCAL) {
                        if (lttng_strncpy(list[idx].ctrl_url,
                                        output->consumer->dst.trace_path,
                                        sizeof(list[idx].ctrl_url))) {
                                ret = -LTTNG_ERR_INVALID;
-                               goto error;
+                               goto error_unlock;
                        }
                } else {
                        /* Control URI. */
@@ -3367,7 +3367,7 @@ ssize_t cmd_snapshot_list_outputs(struct ltt_session *session,
                                        list[idx].ctrl_url, sizeof(list[idx].ctrl_url));
                        if (ret < 0) {
                                ret = -LTTNG_ERR_NOMEM;
-                               goto error;
+                               goto error_unlock;
                        }
 
                        /* Data URI. */
@@ -3375,7 +3375,7 @@ ssize_t cmd_snapshot_list_outputs(struct ltt_session *session,
                                        list[idx].data_url, sizeof(list[idx].data_url));
                        if (ret < 0) {
                                ret = -LTTNG_ERR_NOMEM;
-                               goto error;
+                               goto error_unlock;
                        }
                }
                idx++;
@@ -3384,9 +3384,10 @@ ssize_t cmd_snapshot_list_outputs(struct ltt_session *session,
        *outputs = list;
        list = NULL;
        ret = session->snapshot.nb_output;
+error_unlock:
+       rcu_read_unlock();
 error:
        free(list);
-       rcu_read_unlock();
        return ret;
 }
 
@@ -3397,7 +3398,7 @@ error:
  * Return 0 if the metadata can be generated, a LTTNG_ERR code otherwise.
  */
 static
-int check_metadata_regenerate_support(struct ltt_session *session)
+int check_regenerate_metadata_support(struct ltt_session *session)
 {
        int ret;
 
@@ -3436,7 +3437,7 @@ end:
 }
 
 static
-int ust_metadata_regenerate(struct ltt_ust_session *usess)
+int ust_regenerate_metadata(struct ltt_ust_session *usess)
 {
        int ret = 0;
        struct buffer_reg_uid *uid_reg = NULL;
@@ -3497,7 +3498,7 @@ end:
 }
 
 /*
- * Command LTTNG_METADATA_REGENERATE from the lttng-ctl library.
+ * Command LTTNG_REGENERATE_METADATA from the lttng-ctl library.
  *
  * Ask the consumer to truncate the existing metadata file(s) and
  * then regenerate the metadata. Live and per-pid sessions are not
@@ -3505,19 +3506,19 @@ end:
  *
  * Return 0 on success or else a LTTNG_ERR code.
  */
-int cmd_metadata_regenerate(struct ltt_session *session)
+int cmd_regenerate_metadata(struct ltt_session *session)
 {
        int ret;
 
        assert(session);
 
-       ret = check_metadata_regenerate_support(session);
+       ret = check_regenerate_metadata_support(session);
        if (ret) {
                goto end;
        }
 
        if (session->kernel_session) {
-               ret = kernctl_session_metadata_regenerate(
+               ret = kernctl_session_regenerate_metadata(
                                session->kernel_session->fd);
                if (ret < 0) {
                        ERR("Failed to regenerate the kernel metadata");
@@ -3526,7 +3527,7 @@ int cmd_metadata_regenerate(struct ltt_session *session)
        }
 
        if (session->ust_session) {
-               ret = ust_metadata_regenerate(session->ust_session);
+               ret = ust_regenerate_metadata(session->ust_session);
                if (ret < 0) {
                        ERR("Failed to regenerate the UST metadata");
                        goto end;
@@ -3539,6 +3540,60 @@ end:
        return ret;
 }
 
+/*
+ * Command LTTNG_REGENERATE_STATEDUMP from the lttng-ctl library.
+ *
+ * Ask the tracer to regenerate a new statedump.
+ *
+ * Return 0 on success or else a LTTNG_ERR code.
+ */
+int cmd_regenerate_statedump(struct ltt_session *session)
+{
+       int ret;
+
+       assert(session);
+
+       if (!session->active) {
+               ret = LTTNG_ERR_SESSION_NOT_STARTED;
+               goto end;
+       }
+       ret = 0;
+
+       if (session->kernel_session) {
+               ret = kernctl_session_regenerate_statedump(
+                               session->kernel_session->fd);
+               /*
+                * Currently, the statedump in kernel can only fail if out
+                * of memory.
+                */
+               if (ret < 0) {
+                       if (ret == -ENOMEM) {
+                               ret = LTTNG_ERR_REGEN_STATEDUMP_NOMEM;
+                       } else {
+                               ret = LTTNG_ERR_REGEN_STATEDUMP_FAIL;
+                       }
+                       ERR("Failed to regenerate the kernel statedump");
+                       goto end;
+               }
+       }
+
+       if (session->ust_session) {
+               ret = ust_app_regenerate_statedump_all(session->ust_session);
+               /*
+                * Currently, the statedump in UST always returns 0.
+                */
+               if (ret < 0) {
+                       ret = LTTNG_ERR_REGEN_STATEDUMP_FAIL;
+                       ERR("Failed to regenerate the UST statedump");
+                       goto end;
+               }
+       }
+       DBG("Cmd regenerate statedump for session %s", session->name);
+       ret = LTTNG_OK;
+
+end:
+       return ret;
+}
 
 /*
  * Send relayd sockets from snapshot output to consumer. Ignore request if the