Fix: channel_ust_create: remove channel on agent error

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

diff --git a/src/bin/lttng-sessiond/channel.c b/src/bin/lttng-sessiond/channel.c
index f35410e3ae3fe85c1a7b05e87d3c25e5865795ae..302d3c9e569039910cd8712cfd576190206afe12 100644 (file)
--- a/src/bin/lttng-sessiond/channel.c
+++ b/src/bin/lttng-sessiond/channel.c
@@ -214,9 +214,16 @@ int channel_kernel_create(struct ltt_kernel_session *ksession,
                attr = defattr;
        }
 
+       /*
+        * Set the overwrite mode for this channel based on the session
+        * type unless the client explicitly overrides the channel mode.
+        */
+       if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
+               attr->attr.overwrite = !!ksession->snapshot_mode;
+       }
+
+       /* Enforce mmap output for snapshot sessions. */
        if (ksession->snapshot_mode) {
-               /* Force channel attribute for snapshot mode. */
-               attr->attr.overwrite = 1;
                attr->attr.output = LTTNG_EVENT_MMAP;
        }
 
@@ -293,6 +300,7 @@ int channel_ust_create(struct ltt_ust_session *usess,
        struct ltt_ust_channel *uchan = NULL;
        struct lttng_channel *defattr = NULL;
        enum lttng_domain_type domain = LTTNG_DOMAIN_UST;
+       bool chan_published = false;
 
        assert(usess);
 
@@ -318,9 +326,16 @@ int channel_ust_create(struct ltt_ust_session *usess,
                }
        }
 
+       /*
+        * Set the overwrite mode for this channel based on the session
+        * type unless the client explicitly overrides the channel mode.
+        */
+       if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
+               attr->attr.overwrite = !!usess->snapshot_mode;
+       }
+
+       /* Enforce mmap output for snapshot sessions. */
        if (usess->snapshot_mode) {
-               /* Force channel attribute for snapshot mode. */
-               attr->attr.overwrite = 1;
                attr->attr.output = LTTNG_EVENT_MMAP;
        }
 
@@ -420,6 +435,7 @@ int channel_ust_create(struct ltt_ust_session *usess,
        if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
                                sizeof(uchan->name))) {
                lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
+               chan_published = true;
        } else {
                /*
                 * Copy channel attribute to session if this is metadata so if NO
@@ -439,7 +455,7 @@ int channel_ust_create(struct ltt_ust_session *usess,
                        agt = agent_create(domain);
                        if (!agt) {
                                ret = LTTNG_ERR_NOMEM;
-                               goto error_free_chan;
+                               goto error_remove_chan;
                        }
                        agent_add(agt, usess->agents);
                }
@@ -448,11 +464,11 @@ int channel_ust_create(struct ltt_ust_session *usess,
        free(defattr);
        return LTTNG_OK;
 
+error_remove_chan:
+       if (chan_published) {
+               trace_ust_delete_channel(usess->domain_global.channels, uchan);
+       }
 error_free_chan:
-       /*
-        * No need to remove the channel from the hash table because at this point
-        * it was not added hence the direct call and no call_rcu().
-        */
        trace_ust_destroy_channel(uchan);
 error:
        free(defattr);