trace-graph: Set comm to NULL if field not found

If the event_comm_field has not been set (does not exist)
then we must also set comm to NULL so that later in the
function, it does not reference the comm variable.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/trace-graph.c b/trace-graph.c
index edd106f..f940874 100644
--- a/trace-graph.c
+++ b/trace-graph.c
@@ -1113,6 +1113,8 @@ int trace_graph_check_sched_switch(struct graph_info *ginfo,
                 pevent_read_number_field(ginfo->ftrace_pid_field, record->data, &val);
                 if (comm && ginfo->ftrace_comm_field)
                         *comm = record->data + ginfo->ftrace_comm_field->offset;
+                else
+                        comm = NULL;
                 if (pid)
                         *pid = val;
                 goto out;