Fix: add missing rcu lock for UST lookup

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

diff --git a/src/bin/lttng-sessiond/context.c b/src/bin/lttng-sessiond/context.c
index 74afd4e0cad5ff87d307de751672ad1ae86bad61..ef5e3e1f01b5e62977a48f116f8f2ceb3b72522b 100644 (file)
--- a/src/bin/lttng-sessiond/context.c
+++ b/src/bin/lttng-sessiond/context.c
@@ -108,16 +108,20 @@ static int add_uctx_to_channel(struct ltt_ust_session *usess, int domain,
                goto error;
        }
 
+       rcu_read_lock();
+
        /* Lookup context before adding it */
        lttng_ht_lookup(uchan->ctx, (void *)((unsigned long)uctx->ctx.ctx), &iter);
        uctx_node = lttng_ht_iter_get_node_ulong(&iter);
        if (uctx_node != NULL) {
                ret = -EEXIST;
+               rcu_read_unlock();
                goto error;
        }
 
        /* Add ltt UST context node to ltt UST channel */
        lttng_ht_add_unique_ulong(uchan->ctx, &uctx->node);
+       rcu_read_unlock();
 
        DBG("Context UST %d added to channel %s", uctx->ctx.ctx, uchan->name);
 
@@ -219,6 +223,8 @@ int context_ust_add(struct ltt_ust_session *usess, int domain,
        struct lttng_ht *chan_ht;
        struct ltt_ust_channel *uchan = NULL;
 
+       rcu_read_lock();
+
        /*
         * Define which channel's hashtable to use from the domain or quit if
         * unknown domain.
@@ -250,6 +256,7 @@ int context_ust_add(struct ltt_ust_session *usess, int domain,
                /* Add ctx to channel */
                ret = add_uctx_to_channel(usess, domain, uchan, ctx);
        } else {
+               rcu_read_lock();
                /* Add ctx all events, all channels */
                cds_lfht_for_each_entry(chan_ht->ht, &iter.iter, uchan, node.node) {
                        ret = add_uctx_to_channel(usess, domain, uchan, ctx);
@@ -258,6 +265,7 @@ int context_ust_add(struct ltt_ust_session *usess, int domain,
                                continue;
                        }
                }
+               rcu_read_unlock();
        }
 
        switch (ret) {
@@ -279,5 +287,6 @@ int context_ust_add(struct ltt_ust_session *usess, int domain,
        }
 
 error:
+       rcu_read_unlock();
        return ret;
 }