trace-graph: Only unref plot->gc if it exists

In case the loop breaks out early, we may unref plot->gc even
though it does not exist.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/trace-graph.c b/trace-graph.c
index 2ddd283..65af0db 100644
--- a/trace-graph.c
+++ b/trace-graph.c
@@ -1894,7 +1894,8 @@ out:
                 plot = ginfo->plot_array[i];
                 draw_plot(ginfo, plot, NULL);
                 trace_graph_plot_end(ginfo, plot);
-                gdk_gc_unref(plot->gc);
+                if (plot->gc)
+                        gdk_gc_unref(plot->gc);
                 plot->gc = NULL;
         }
 }