From: Mathieu Desnoyers Date: Thu, 17 Sep 2015 16:48:40 +0000 (-0400) Subject: Fix: relayd: don't call lttng_ht_destroy in RCU read-side C.S. X-Git-Tag: v2.7.0-rc2~12 X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=c65ce45581a476c68bafc73a0300eaa168dc1bd6;p=lttng-tools.git Fix: relayd: don't call lttng_ht_destroy in RCU read-side C.S. It is forbidden to call lttng_ht_destroy() within a RCU read-side critical section. Signed-off-by: Mathieu Desnoyers Signed-off-by: Jérémie Galarneau --- diff --git a/src/bin/lttng-relayd/session.c b/src/bin/lttng-relayd/session.c index 14ae874ea..2300e5f1a 100644 --- a/src/bin/lttng-relayd/session.c +++ b/src/bin/lttng-relayd/session.c @@ -131,7 +131,14 @@ static void rcu_destroy_session(struct rcu_head *rcu_head) struct relay_session *session = caa_container_of(rcu_head, struct relay_session, rcu_node); - + /* + * Since each trace has a reference on the session, it means + * that if we are at the point where we teardown the session, no + * trace belonging to that session exist at this point. + * Calling lttng_ht_destroy in call_rcu worker thread so we + * don't hold the RCU read-side lock while calling it. + */ + lttng_ht_destroy(session->ctf_traces_ht); free(session); } @@ -155,12 +162,6 @@ static void destroy_session(struct relay_session *session) ret = session_delete(session); assert(!ret); - /* - * Since each trace has a reference on the session, it means - * that if we are at the point where we teardown the session, no - * trace belonging to that session exist at this point. - */ - lttng_ht_destroy(session->ctf_traces_ht); call_rcu(&session->rcu_node, rcu_destroy_session); } diff --git a/src/bin/lttng-relayd/stream.c b/src/bin/lttng-relayd/stream.c index b604919a7..8825d094c 100644 --- a/src/bin/lttng-relayd/stream.c +++ b/src/bin/lttng-relayd/stream.c @@ -253,6 +253,11 @@ static void stream_unpublish(struct relay_stream *stream) static void stream_destroy(struct relay_stream *stream) { if (stream->indexes_ht) { + /* + * Calling lttng_ht_destroy in call_rcu worker thread so + * we don't hold the RCU read-side lock while calling + * it. + */ lttng_ht_destroy(stream->indexes_ht); } if (stream->tfa) {