Fix: deinitialization of the shared plugin crash (#1114)

Fix gst mtl shared plugin deinitialization
function naive approach to the plugins in the
shared pipline space, making sure the
plugins cannot abuse the shared counter by
reseting their handle to NULL>

Author: DawidWesierski4

ecosystem/gstreamer_plugin/gst_mtl_common.c

@@ -659,6 +659,8 @@ mtl_handle gst_mtl_common_init_handle(GeneralArgs* general_args,
   }
 
   common_handle.mtl_handle_reference_count++;
+  GST_INFO("MTL shared handle reference count incremented to: %d",
+           common_handle.mtl_handle_reference_count);
   common_handle.mtl_handle = handle;
   pthread_mutex_unlock(&common_handle.mutex);
   return common_handle.mtl_handle;
@@ -669,11 +671,8 @@ mtl_handle gst_mtl_common_init_handle(GeneralArgs* general_args,
  * If the handle is the shared handle, the reference count is decremented.
  * If the reference count reaches zero, the handle is deinitialized.
  * If the handle is not the shared handle, it is deinitialized immediately.
- *
- * @param handle MTL handle to deinitialize (Null is an acceptable value then
- * shared value will be used).
  */
-gint gst_mtl_common_deinit_handle(mtl_handle handle) {
+gint gst_mtl_common_deinit_handle(mtl_handle* handle) {
   gint ret;
 
   if (!handle) {
@@ -682,23 +681,33 @@ gint gst_mtl_common_deinit_handle(mtl_handle handle) {
   }
 
   pthread_mutex_lock(&common_handle.mutex);
-  if (handle == common_handle.mtl_handle) {
+
+  if (*handle == common_handle.mtl_handle) {
     common_handle.mtl_handle_reference_count--;
 
     if (common_handle.mtl_handle_reference_count > 0) {
+      GST_INFO("Shared handle is still in use, reference count: %d",
+               common_handle.mtl_handle_reference_count);
       pthread_mutex_unlock(&common_handle.mutex);
       return 0;
+    } else if (common_handle.mtl_handle_reference_count < 0) {
+      GST_ERROR("Invalid reference count: %d", common_handle.mtl_handle_reference_count);
+      pthread_mutex_unlock(&common_handle.mutex);
+      return -EINVAL;
     }
+
+    GST_INFO("Deinitializing shared handle");
   }
 
-  ret = mtl_stop(handle);
+  ret = mtl_stop(*handle);
   if (ret) {
     GST_ERROR("Failed to stop MTL library");
     pthread_mutex_unlock(&common_handle.mutex);
     return ret;
   }
 
-  ret = mtl_uninit(handle);
+  ret = mtl_uninit(*handle);
+  *handle = NULL;
   pthread_mutex_unlock(&common_handle.mutex);
   return ret;
 }

ecosystem/gstreamer_plugin/gst_mtl_common.h

@@ -67,9 +67,9 @@ typedef struct GeneralArgs {
 } GeneralArgs;
 
 typedef struct SessionPortArgs {
-  gchar session_ip_string[MTL_PORT_MAX][MTL_PORT_MAX_LEN];
-  gchar port[MTL_PORT_MAX][MTL_PORT_MAX_LEN];
-  gint udp_port[MTL_PORT_MAX];
+  gchar session_ip_string[2][MTL_PORT_MAX_LEN];
+  gchar port[2][MTL_PORT_MAX_LEN];
+  gint udp_port[2];
   gint payload_type;
 } SessionPortArgs;
 
@@ -108,5 +108,5 @@ void gst_mtl_common_get_general_arguments(GObject* object, guint prop_id,
 mtl_handle gst_mtl_common_init_handle(GeneralArgs* generalArgs,
                                       gboolean force_to_initialize_new_instance);
 
-gint gst_mtl_common_deinit_handle(mtl_handle handle);
+gint gst_mtl_common_deinit_handle(mtl_handle* handle);
 #endif /* __GST_MTL_COMMON_H__ */

ecosystem/gstreamer_plugin/gst_mtl_st20p_rx.c

@@ -495,7 +495,7 @@ static void gst_mtl_st20p_rx_finalize(GObject* object) {
   }
 
   if (src->mtl_lib_handle) {
-    if (gst_mtl_common_deinit_handle(src->mtl_lib_handle)) {
+    if (gst_mtl_common_deinit_handle(&src->mtl_lib_handle)) {
       GST_ERROR("Failed to uninitialize MTL library");
       return;
     }

ecosystem/gstreamer_plugin/gst_mtl_st20p_tx.c

@@ -482,7 +482,7 @@ static void gst_mtl_st20p_tx_finalize(GObject* object) {
   }
 
   if (sink->mtl_lib_handle) {
-    if (gst_mtl_common_deinit_handle(sink->mtl_lib_handle))
+    if (gst_mtl_common_deinit_handle(&sink->mtl_lib_handle))
       GST_ERROR("Failed to uninitialize MTL library");
   }
 }

ecosystem/gstreamer_plugin/gst_mtl_st30p_rx.c

@@ -464,7 +464,7 @@ static void gst_mtl_st30p_rx_finalize(GObject* object) {
   }
 
   if (src->mtl_lib_handle) {
-    if (gst_mtl_common_deinit_handle(src->mtl_lib_handle)) {
+    if (gst_mtl_common_deinit_handle(&src->mtl_lib_handle)) {
       GST_ERROR("Failed to uninitialize MTL library");
       return;
     }

ecosystem/gstreamer_plugin/gst_mtl_st30p_tx.c

@@ -535,7 +535,7 @@ static void gst_mtl_st30p_tx_finalize(GObject* object) {
   }
 
   if (sink->mtl_lib_handle) {
-    if (gst_mtl_common_deinit_handle(sink->mtl_lib_handle))
+    if (gst_mtl_common_deinit_handle(&sink->mtl_lib_handle))
       GST_ERROR("Failed to uninitialize MTL library");
   }
 }

ecosystem/gstreamer_plugin/gst_mtl_st40_rx.c

@@ -485,7 +485,7 @@ static void gst_mtl_st40_rx_finalize(GObject* object) {
   pthread_cond_destroy(&src->mbuff_cond);
 
   if (src->mtl_lib_handle) {
-    if (gst_mtl_common_deinit_handle(src->mtl_lib_handle)) {
+    if (gst_mtl_common_deinit_handle(&src->mtl_lib_handle)) {
       GST_ERROR("Failed to uninitialize MTL library");
     }
   }

ecosystem/gstreamer_plugin/gst_mtl_st40p_tx.c

@@ -460,7 +460,7 @@ static void gst_mtl_st40p_tx_finalize(GObject* object) {
   }
 
   if (sink->mtl_lib_handle) {
-    if (gst_mtl_common_deinit_handle(sink->mtl_lib_handle)) {
+    if (gst_mtl_common_deinit_handle(&sink->mtl_lib_handle)) {
       GST_ERROR("Failed to uninitialize MTL library");
       return;
     }