Hello,
Please review the fix for the following issue: https://bugs.openjdk.java.net/browse/JDK-8244088 The scenario is: Every-time we tried to switch a Gnome theme, Java ended up n deadlocked UI. This regression was introduced (by below patches) while Providing GTK3 support in Java Java8: 8207322: Backport GTK3 support on Linux to 8u JDK11 : 8145547: [AWT/Swing] Conditional support for GTK 3 on Linux Here for GTK3's g_main_context_iteration they have included an extra lock which was causing a deadlock and also the JNDI corresponding module is defined using a single parameter causing the hang in XToolkit_waitForEvents So the fix is in 2 parts: 1) In Java_com_sun_java_swing_plaf_gtk_GTKEngine_native_1switch_1theme () method we wrap the g_main_context_iteration (ie, gtk->flush_event_loop() ) with gdk_threads_enter/gdk_threads_exit while g_main_context_iteration itself takes care of locks. -> Remove the extra lock 2) The definition of g_main_context_iteration in new “gtk3_interface.h” was wrongly written with a single parameter, like : static gboolean (*fp_g_main_context_iteration)(GMainContext *context); instead of https://developer.gnome.org/glib/stable/glib-The-Main-Event- Loop.html#g-main-context-iteration gboolean g_main_context_iteration (GMainContext *context, gboolean may_block); -> When the above definition was corrected, we stopped seeing the hang during polling. The proposed changeset is: --- old/src/java.desktop/unix/native/libawt_xawt/awt/gtk3_interface.c 2020-08-25 16:57:34.000000000 +0530 1 of 2 26/08/20, 11:21 am https://mail.notes.na.collabserv.com/data2/126/21004100.nsf/0/... +++ new/src/java.desktop/unix/native/libawt_xawt/awt/gtk3_interface.c 2020-08-25 16:57:34.000000000 +0530 @@ -703,7 +703,7 @@ */ static void flush_gtk_event_loop() { - while((*fp_g_main_context_iteration)(NULL)); + while((*fp_g_main_context_iteration)(NULL, FALSE)); } /* --- old/src/java.desktop/unix/native/libawt_xawt/awt/gtk3_interface.h 2020-08-25 16:57:36.000000000 +0530 +++ new/src/java.desktop/unix/native/libawt_xawt/awt/gtk3_interface.h 2020-08-25 16:57:35.000000000 +0530 @@ -396,7 +396,7 @@ const gchar *first_property_name, ...); -static gboolean (*fp_g_main_context_iteration)(GMainContext *context); +static gboolean (*fp_g_main_context_iteration)(GMainContext *context, gboolean may_block); static gboolean (*fp_g_str_has_prefix)(const gchar *str, const gchar *prefix); static gchar** (*fp_g_strsplit)(const gchar *string, const gchar *delimiter, gint max_tokens); --- old/src/java.desktop/unix/native/libawt_xawt/awt/swing_GTKEngine.c 2020-08-25 16:57:37.000000000 +0530 +++ new/src/java.desktop/unix/native/libawt_xawt/awt/swing_GTKEngine.c 2020-08-25 16:57:37.000000000 +0530 @@ -346,10 +346,8 @@ JNIEXPORT void JNICALL Java_com_sun_java_swing_plaf_gtk_GTKEngine_native_1switch_1theme( JNIEnv *env, jobject this) { - // Note that flush_gtk_event_loop takes care of locks (7053002) - gtk->gdk_threads_enter(); + // Note that gtk->flush_event_loop takes care of locks (7053002) gtk->flush_event_loop(); - gtk->gdk_threads_leave(); } /* Thanks Jay
