segmentation fault - segfault in c/gtk+3 program -

structs defined inside header:

struct info{     gint mode, issignalactivate;     gchar *filename;     gtkwidget *pwdentry, *pwdreentry, *mainwin, *dialog, *file_dialog; }; extern struct info s_info;  struct hashes{     gchar *filename;     gtkwidget *entrymd5, *entrys1, *entrys256, *entrys512, *entrywhir, *entryrmd;     gtkwidget *checkmd5, *checks1, *checks256, *checks512, *checkwhir, *checkrmd; }; extern struct hashes s_hashtype; 

and main part of program:

int main(int argc, char **argv){     if(!gcry_check_version(gcrypt_min_ver)){         fputs("libgcrypt min version required: 1.5.0\n", stderr);         return -1;     }     gcry_control(gcryctl_init_secmem, 16384, 0);     gcry_control(gcryctl_initialization_finished, 0);      gtkapplication *app;     int status;      app = gtk_application_new ("org.gtk.polcrypt",g_application_flags_none);     g_signal_connect (app, "startup", g_callback (startup), null);     g_signal_connect (app, "activate", g_callback (activate), null);     status = g_application_run (g_application (app), argc, argv);     g_object_unref (app);     return status; }  static void startup (gtkapplication *application, gpointer user_data __attribute__ ((unused))) {   static const gactionentry actions[] = {     { "about", },     { "quit", quit }   };    gmenu *menu;    g_action_map_add_action_entries (g_action_map (application), actions, g_n_elements (actions), application);    menu = g_menu_new ();   g_menu_append (menu, "about", "app.about");   g_menu_append (menu, "quit",  "app.quit");   gtk_application_set_app_menu (application, g_menu_model (menu));   g_object_unref (menu); }  static void activate (gtkapplication *app, gpointer user_data __attribute__ ((unused))) {     gtkwidget *butha, *grid;     struct info s_info;      s_info.mainwin = gtk_application_window_new(app);     gtk_window_set_application (gtk_window (s_info.mainwin), gtk_application (app));     gtk_window_set_position(gtk_window(s_info.mainwin), gtk_win_pos_center);     gtk_window_set_title(gtk_window(s_info.mainwin), "polcrypt");     gtk_window_set_resizable(gtk_window(s_info.mainwin), false);     gtk_container_set_border_width(gtk_container(s_info.mainwin), 10);      butha = gtk_button_new_with_label("compute hash");     g_signal_connect(butha, "clicked", g_callback (is_hash), &s_info);      grid = gtk_grid_new();     gtk_container_add(gtk_container(s_info.mainwin), grid);     gtk_grid_set_row_homogeneous(gtk_grid(grid), true);     gtk_grid_set_column_homogeneous(gtk_grid(grid), true);     gtk_grid_set_row_spacing(gtk_grid(grid), 5);     gtk_grid_set_column_spacing(gtk_grid(grid), 5);      //numero colonna, numero riga, colonne da occupare, righe da occupare. colonne e righe sono aggiunte automaticamente     gtk_grid_attach(gtk_grid(grid), butha, 0, 0, 5, 1);      gtk_widget_show_all(s_info.mainwin); }  static void is_hash(gtkwidget *ignored __attribute__ ((unused)), struct info *s_info){     s_info->mode = 3;     file_dialog(s_info); }  static void file_dialog(struct info *s_info){     s_info->file_dialog =  gtk_file_chooser_dialog_new("choose file", null, gtk_file_chooser_action_open, ("_cancel"), gtk_response_cancel, ("_ok"), gtk_response_accept, null);     if (gtk_dialog_run (gtk_dialog (s_info->file_dialog)) == gtk_response_accept){         s_info->filename = gtk_file_chooser_get_filename (gtk_file_chooser (s_info->file_dialog));         if(s_info->mode == 3){             select_hash_type(s_info);             g_free (s_info->filename);         }     }     gtk_widget_destroy (s_info->file_dialog); }  static void select_hash_type(struct info *s_infohash){     gtk_widget_hide(gtk_widget(s_infohash->file_dialog));     struct hashes s_hashtype;     gtkwidget *content_area, *grid2;     s_infohash->dialog = gtk_dialog_new_with_buttons ("select hash", null, gtk_dialog_modal | gtk_dialog_destroy_with_parent, "_quit", gtk_response_close, null);     content_area = gtk_dialog_get_content_area (gtk_dialog (s_infohash->dialog));      s_hashtype.checkmd5 = gtk_check_button_new_with_label("md5");      s_hashtype.entrymd5 = gtk_entry_new();      gtk_editable_set_editable(gtk_editable(s_hashtype.entrymd5), false);      gtk_widget_set_size_request(s_infohash->dialog, 250, 150); // richiedo una grandezza minima      grid2 = gtk_grid_new();     gtk_grid_set_row_homogeneous(gtk_grid(grid2), true); // righe stessa altezza     gtk_grid_set_column_homogeneous(gtk_grid(grid2), true); // colonne stessa larghezza     gtk_grid_set_row_spacing(gtk_grid(grid2), 5); // spazio fra le righe      // numero colonna, numero riga, colonne da occupare, righe da occupare     gtk_grid_attach(gtk_grid(grid2), s_hashtype.checkmd5, 0, 0, 1, 1);     gtk_grid_attach(gtk_grid(grid2), s_hashtype.entrymd5, 2, 0, 6, 1);      /* add grid, , show we've added dialog */     gtk_container_add (gtk_container (content_area), grid2);     gtk_widget_show_all (s_infohash->dialog);      s_hashtype.filename = malloc(strlen(s_infohash->filename)+1);     strcpy(s_hashtype.filename, s_infohash->filename);      g_signal_connect_swapped(s_hashtype.checkmd5, "clicked", g_callback(compute_md5), &s_hashtype);      gint result = gtk_dialog_run(gtk_dialog(s_infohash->dialog));     switch(result){         case gtk_response_close:             gtk_widget_destroy(s_infohash->dialog);             break;     }     free(s_hashtype.filename); } 

my problem program segfault when clicking on "quit" button of s_infohash->dialog.
above there output of gdb.

program received signal sigsegv, segmentation fault. 0x00000000009aa4f0 in ?? () (gdb) #0  0x00000000009aa4f0 in ?? () #1  0x00000000008f2290 in ?? () #2  0x00007fffffffd330 in ?? () #3  0x00000000007e0480 in ?? () #4  0x0000000000000188 in ?? () #5  0x0000000040000002 in ?? () #6  0x00007ffff5afbba9 in g_hash_table_lookup ()    /usr/lib64/libglib-2.0.so.0 #7  0x00007ffff5e17b7f in g_signal_emit_valist ()    /usr/lib64/libgobject-2.0.so.0 #8  0x00007ffff5e1881a in g_signal_emit () /usr/lib64/libgobject-2.0.so.0 #9  0x00007ffff76be454 in ?? () /usr/lib64/libgtk-3.so.0 #10 0x00007ffff75943dc in ?? () /usr/lib64/libgtk-3.so.0 #11 0x00007ffff7595c2a in gtk_main_do_event () /usr/lib64/libgtk-3.so.0 #12 0x00007ffff71ac522 in ?? () /usr/lib64/libgdk-3.so.0 #13 0x00007ffff5b0bc66 in g_main_context_dispatch ()    /usr/lib64/libglib-2.0.so.0 #14 0x00007ffff5b0bfb8 in ?? () /usr/lib64/libglib-2.0.so.0 #15 0x00007ffff5b0c05c in g_main_context_iteration ()    /usr/lib64/libglib-2.0.so.0 #16 0x00007ffff60d9eec in g_application_run () /usr/lib64/libgio-2.0.so.0 #17 0x0000000000403339 in main (argc=1, argv=0x7fffffffd878)     @ src/gtk3/main-gui.c:35 

this thing driving me crazy because cannot find causing segfault... (i know gdb gtk_application_run (#17) mean? how can debug , fix thing?)

i'm using gcc 4.8.1 , gtk+ 3.10

s_info cease exist after leaving activate(), whenever signal issued accessing invalid memory chunk (formerly occupied s_info , pointed &s_info pass user_data signal callback)