From 6ffddd27e5216a142bfd882c5375f0816303b136 Mon Sep 17 00:00:00 2001 From: He Junyan Date: Fri, 6 Nov 2020 14:05:39 +0800 Subject: [PATCH] glimagesink: Avoid assert in query. The sink_query just uses context, other_context and display to query info. But all these objects can be changed or distroyed in state_change() func and other places. This patch is not very perfect. The condition race still exists in other places in this element. All the functions directly access these objects without protection. Most of them are executed when the data is pushing and draw context/window have already been established, so they should not have problems. But the sink_query and propose_allocation functions are the query -like functions and executed in query context, which can be called in any state of the element. So it can cause some crash issues because of destroyed context object. Part-of: --- ext/gl/gstglimagesink.c | 131 ++++++++++++++++++++++++++++++++++++------------ 1 file changed, 99 insertions(+), 32 deletions(-) diff --git a/ext/gl/gstglimagesink.c b/ext/gl/gstglimagesink.c index b403b4c..2c023ce 100644 --- a/ext/gl/gstglimagesink.c +++ b/ext/gl/gstglimagesink.c @@ -965,6 +965,39 @@ gst_glimage_sink_mouse_scroll_event_cb (GstGLWindow * window, posx, posy, delta_x, delta_y); } +static void +_set_context (GstGLImageSink * gl_sink, GstGLContext * context) +{ + GST_GLIMAGE_SINK_LOCK (gl_sink); + if (gl_sink->context) + gst_object_unref (gl_sink->context); + + gl_sink->context = context; + GST_GLIMAGE_SINK_UNLOCK (gl_sink); +} + +static void +_set_other_context (GstGLImageSink * gl_sink, GstGLContext * other_context) +{ + GST_GLIMAGE_SINK_LOCK (gl_sink); + if (gl_sink->other_context) + gst_object_unref (gl_sink->other_context); + + gl_sink->other_context = other_context; + GST_GLIMAGE_SINK_UNLOCK (gl_sink); +} + +static void +_set_display (GstGLImageSink * gl_sink, GstGLDisplay * display) +{ + GST_GLIMAGE_SINK_LOCK (gl_sink); + if (gl_sink->display) + gst_object_unref (gl_sink->display); + + gl_sink->display = display; + GST_GLIMAGE_SINK_UNLOCK (gl_sink); +} + static gboolean _ensure_gl_setup (GstGLImageSink * gl_sink) { @@ -976,12 +1009,10 @@ _ensure_gl_setup (GstGLImageSink * gl_sink) GST_OBJECT_LOCK (gl_sink->display); do { GstGLContext *other_context = NULL; + GstGLContext *context = NULL; GstGLWindow *window = NULL; - if (gl_sink->context) { - gst_object_unref (gl_sink->context); - gl_sink->context = NULL; - } + _set_context (gl_sink, NULL); GST_DEBUG_OBJECT (gl_sink, "No current context, creating one for %" GST_PTR_FORMAT, @@ -995,12 +1026,14 @@ _ensure_gl_setup (GstGLImageSink * gl_sink) } if (!gst_gl_display_create_context (gl_sink->display, - other_context, &gl_sink->context, &error)) { + other_context, &context, &error)) { if (other_context) gst_object_unref (other_context); GST_OBJECT_UNLOCK (gl_sink->display); goto context_error; } + _set_context (gl_sink, context); + context = NULL; GST_DEBUG_OBJECT (gl_sink, "created context %" GST_PTR_FORMAT " from other context %" @@ -1062,10 +1095,7 @@ context_error: GST_ELEMENT_ERROR (gl_sink, RESOURCE, NOT_FOUND, ("%s", error->message), (NULL)); - if (gl_sink->context) { - gst_object_unref (gl_sink->context); - gl_sink->context = NULL; - } + _set_context (gl_sink, NULL); g_clear_error (&error); @@ -1134,10 +1164,30 @@ gst_glimage_sink_query (GstBaseSink * bsink, GstQuery * query) switch (GST_QUERY_TYPE (query)) { case GST_QUERY_CONTEXT: { - if (gst_gl_handle_context_query ((GstElement *) glimage_sink, query, - glimage_sink->display, glimage_sink->context, - glimage_sink->other_context)) - return TRUE; + GstGLContext *context = NULL; + GstGLContext *other_context = NULL; + GstGLDisplay *display = NULL; + + GST_GLIMAGE_SINK_LOCK (bsink); + if (glimage_sink->context) + context = gst_object_ref (glimage_sink->context); + if (glimage_sink->other_context) + other_context = gst_object_ref (glimage_sink->other_context); + if (glimage_sink->display) + display = gst_object_ref (glimage_sink->display); + GST_GLIMAGE_SINK_UNLOCK (bsink); + + res = gst_gl_handle_context_query ((GstElement *) glimage_sink, query, + display, context, other_context); + + if (context) + gst_object_unref (context); + if (other_context) + gst_object_unref (other_context); + if (display) + gst_object_unref (display); + if (res) + return res; break; } case GST_QUERY_DRAIN: @@ -1176,9 +1226,12 @@ static void gst_glimage_sink_set_context (GstElement * element, GstContext * context) { GstGLImageSink *gl_sink = GST_GLIMAGE_SINK (element); + GstGLContext *other_context = NULL; + GstGLDisplay *display = NULL; - gst_gl_handle_set_context (element, context, &gl_sink->display, - &gl_sink->other_context); + gst_gl_handle_set_context (element, context, &display, &other_context); + _set_other_context (gl_sink, other_context); + _set_display (gl_sink, display); if (gl_sink->display) gst_gl_display_filter_gl_api (gl_sink->display, SUPPORTED_GL_APIS); @@ -1191,6 +1244,7 @@ gst_glimage_sink_change_state (GstElement * element, GstStateChange transition) { GstGLImageSink *glimage_sink; GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS; + GstGLContext *context; GST_DEBUG ("changing state: %s => %s", gst_element_state_get_name (GST_STATE_TRANSITION_CURRENT (transition)), @@ -1277,8 +1331,14 @@ gst_glimage_sink_change_state (GstElement * element, GstStateChange transition) glimage_sink->overlay_compositor = NULL; } - if (glimage_sink->context) { - GstGLWindow *window = gst_gl_context_get_window (glimage_sink->context); + context = NULL; + GST_GLIMAGE_SINK_LOCK (glimage_sink); + if (glimage_sink->context) + context = gst_object_ref (glimage_sink->context); + GST_GLIMAGE_SINK_UNLOCK (glimage_sink); + + if (context) { + GstGLWindow *window = gst_gl_context_get_window (context); gst_gl_window_send_message (window, GST_GL_WINDOW_CB (gst_glimage_sink_cleanup_glthread), glimage_sink); @@ -1299,21 +1359,15 @@ gst_glimage_sink_change_state (GstElement * element, GstStateChange transition) glimage_sink->mouse_scroll_sig_id = 0; gst_object_unref (window); - gst_object_unref (glimage_sink->context); - glimage_sink->context = NULL; + _set_context (glimage_sink, NULL); + + gst_object_unref (context); } glimage_sink->window_id = 0; - if (glimage_sink->other_context) { - gst_object_unref (glimage_sink->other_context); - glimage_sink->other_context = NULL; - } - - if (glimage_sink->display) { - gst_object_unref (glimage_sink->display); - glimage_sink->display = NULL; - } + _set_other_context (glimage_sink, NULL); + _set_display (glimage_sink, NULL); break; default: break; @@ -1939,10 +1993,19 @@ gst_glimage_sink_propose_allocation (GstBaseSink * bsink, GstQuery * query) guint size; gboolean need_pool; GstStructure *allocation_meta = NULL; + GstGLContext *context = NULL; if (!_ensure_gl_setup (glimage_sink)) return FALSE; + GST_GLIMAGE_SINK_LOCK (glimage_sink); + if (glimage_sink->context) + context = gst_object_ref (glimage_sink->context); + GST_GLIMAGE_SINK_UNLOCK (glimage_sink); + + if (!context) + return FALSE; + gst_query_parse_allocation (query, &caps, &need_pool); if (caps == NULL) @@ -1957,7 +2020,7 @@ gst_glimage_sink_propose_allocation (GstBaseSink * bsink, GstQuery * query) if (need_pool) { GST_DEBUG_OBJECT (glimage_sink, "create new pool"); - pool = gst_gl_buffer_pool_new (glimage_sink->context); + pool = gst_gl_buffer_pool_new (context); config = gst_buffer_pool_get_config (pool); gst_buffer_pool_config_set_params (config, caps, size, 0, 0); gst_buffer_pool_config_add_option (config, @@ -1974,7 +2037,7 @@ gst_glimage_sink_propose_allocation (GstBaseSink * bsink, GstQuery * query) if (pool) g_object_unref (pool); - if (glimage_sink->context->gl_vtable->FenceSync) + if (context->gl_vtable->FenceSync) gst_query_add_allocation_meta (query, GST_GL_SYNC_META_API_TYPE, 0); if (glimage_sink->window_width != 0 && glimage_sink->window_height != 0) { @@ -1994,21 +2057,25 @@ gst_glimage_sink_propose_allocation (GstBaseSink * bsink, GstQuery * query) if (allocation_meta) gst_structure_free (allocation_meta); + gst_object_unref (context); return TRUE; /* ERRORS */ no_caps: { + gst_object_unref (context); GST_WARNING_OBJECT (bsink, "no caps specified"); return FALSE; } invalid_caps: { + gst_object_unref (context); GST_WARNING_OBJECT (bsink, "invalid caps specified"); return FALSE; } config_failed: { + gst_object_unref (context); GST_WARNING_OBJECT (bsink, "failed setting config"); return FALSE; } @@ -2274,10 +2341,10 @@ gst_glimage_sink_on_draw (GstGLImageSink * gl_sink) g_return_if_fail (GST_IS_GLIMAGE_SINK (gl_sink)); - gl = gl_sink->context->gl_vtable; - GST_GLIMAGE_SINK_LOCK (gl_sink); + gl = gl_sink->context->gl_vtable; + /* check if texture is ready for being drawn */ if (!gl_sink->redisplay_texture) { GST_GLIMAGE_SINK_UNLOCK (gl_sink); -- 2.7.4