diff --git a/src/libkshark-plugin.c b/src/libkshark-plugin.c
index ebd2579..09886ce 100644
--- a/src/libkshark-plugin.c
+++ b/src/libkshark-plugin.c
@@ -117,6 +117,9 @@ int kshark_unregister_event_handler(struct kshark_data_stream *stream,
 {
 	struct kshark_event_proc_handler **last;
 
+	if (stream->stream_id < 0)
+		return 0;
+
 	for (last = &stream->event_handlers; *last; last = &(*last)->next) {
 		if ((*last)->id == event_id &&
 		    (*last)->event_func == evt_func) {
@@ -182,6 +185,9 @@ void kshark_unregister_draw_handler(struct kshark_data_stream *stream,
 {
 	struct kshark_draw_handler **last;
 
+	if (stream->stream_id < 0)
+		return;
+
 	for (last = &stream->draw_handlers; *last; last = &(*last)->next) {
 		if ((*last)->draw_func == draw_func) {
 			struct kshark_draw_handler *this_handler;
@@ -410,12 +416,16 @@ void kshark_unregister_plugin(struct kshark_context *kshark_ctx,
  */
 void kshark_free_plugin_list(struct kshark_plugin_list *plugins)
 {
+	struct kshark_data_stream stream;
 	struct kshark_plugin_list *last;
 
+	stream.stream_id = KS_PLUGIN_CONTEXT_FREE;
 	while (plugins) {
 		last = plugins;
 		plugins = plugins->next;
 
+		if (last->process_interface)
+			last->process_interface->close(&stream);
 		free_plugin(last);
 	}
 }
diff --git a/src/libkshark-plugin.h b/src/libkshark-plugin.h
index 752dbeb..b259b24 100644
--- a/src/libkshark-plugin.h
+++ b/src/libkshark-plugin.h
@@ -366,6 +366,9 @@ int kshark_handle_all_dpis(struct kshark_data_stream *stream,
 	__ok;								\
 })									\
 
+/** Identifier used to free the plugin context. */
+#define KS_PLUGIN_CONTEXT_FREE	-1
+
 /**
  * General purpose macro defining methods for adding plugin context.
  * Do not use this macro in header files.
@@ -393,21 +396,25 @@ __hidden type *__init(int sd)						\
 	__context_handler[sd] = obj;					\
 	return obj;							\
 }									\
+__hidden type *__get_context(int sd)					\
+{									\
+	if (sd < 0 || sd >= __n_streams)				\
+		return NULL;						\
+	return __context_handler[sd];					\
+}									\
 __hidden void __close(int sd)						\
 {									\
-	if (sd < 0) {							\
+	type *obj;							\
+	if (sd == KS_PLUGIN_CONTEXT_FREE) {				\
 		free(__context_handler);				\
 		__n_streams = -1;					\
 		return;							\
 	}								\
-	free(__context_handler[sd]);					\
-	__context_handler[sd] = NULL;					\
-}									\
-__hidden type *__get_context(int sd)					\
-{									\
-	if (sd < 0 || sd >= __n_streams)				\
-		return NULL;						\
-	return __context_handler[sd];					\
+	obj = __get_context(sd);					\
+	if (obj) {							\
+		free(__context_handler[sd]);				\
+		__context_handler[sd] = NULL;				\
+	}								\
 }									\
 
 /**
diff --git a/src/libkshark.h b/src/libkshark.h
index aa4b3ca..ee3a1d3 100644
--- a/src/libkshark.h
+++ b/src/libkshark.h
@@ -281,7 +281,7 @@ struct kshark_generic_stream_interface {
 /** Structure representing a stream of trace data. */
 struct kshark_data_stream {
 	/** Data stream identifier. */
-	uint16_t		stream_id;
+	int16_t			stream_id;
 
 	/** The number of CPUs presented in this data stream. */
 	int			n_cpus;
diff --git a/src/plugins/sched_events.c b/src/plugins/sched_events.c
index 5798322..f3c2c23 100644
--- a/src/plugins/sched_events.c
+++ b/src/plugins/sched_events.c
@@ -198,26 +198,26 @@ int KSHARK_PLOT_PLUGIN_INITIALIZER(struct kshark_data_stream *stream)
 int KSHARK_PLOT_PLUGIN_DEINITIALIZER(struct kshark_data_stream *stream)
 {
 	printf("<-- sched close %i\n", stream->stream_id);
-	struct plugin_sched_context *plugin_ctx;
-	int sd = stream->stream_id;
+	struct plugin_sched_context *plugin_ctx = __get_context(stream->stream_id);
+	int ret = 0;
 
-	plugin_ctx = __get_context(sd);
-	if (!plugin_ctx)
-		return 0;
+	if (plugin_ctx) {
+		kshark_unregister_event_handler(stream,
+						plugin_ctx->sched_switch_event->id,
+						plugin_sched_swith_action);
 
-	kshark_unregister_event_handler(stream,
-					plugin_ctx->sched_switch_event->id,
-					plugin_sched_swith_action);
+		kshark_unregister_event_handler(stream,
+						plugin_ctx->sched_waking_event->id,
+						plugin_sched_wakeup_action);
 
-	kshark_unregister_event_handler(stream,
-					plugin_ctx->sched_waking_event->id,
-					plugin_sched_wakeup_action);
+		kshark_unregister_draw_handler(stream, plugin_draw);
 
-	kshark_unregister_draw_handler(stream, plugin_draw);
+		ret = 1;
+	}
 
-	__close(sd);
+	__close(stream->stream_id);
 
-	return 1;
+	return ret;
 }
 
 /** Initialize the control interface of the plugin. */
