diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index eb4cd6d2f60..309d0210071 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -14061,6 +14061,7 @@ static struct cmd_list_element *show_ada_list;
 static void
 ada_new_objfile_observer (struct objfile *objfile)
 {
+  gdb_assert (objfile != nullptr);
   ada_clear_symbol_cache (objfile->pspace ());
 }
 
diff --git a/gdb/ada-tasks.c b/gdb/ada-tasks.c
index 0e124e1a2a2..ecf08bc144c 100644
--- a/gdb/ada-tasks.c
+++ b/gdb/ada-tasks.c
@@ -1468,6 +1468,7 @@ ada_tasks_clear_pspace_data (program_space *pspace)
 static void
 ada_tasks_new_objfile_observer (objfile *objfile)
 {
+  gdb_assert (objfile != nullptr);
   ada_tasks_clear_pspace_data (objfile->pspace ());
 }
 
diff --git a/gdb/agent.c b/gdb/agent.c
index beeaf62b552..533f9aaf657 100644
--- a/gdb/agent.c
+++ b/gdb/agent.c
@@ -70,6 +70,8 @@ agent_new_objfile (struct objfile *objfile)
   if (can_use_agent == can_use_agent_off)
     return;
 
+  gdb_assert (objfile != nullptr);
+
   agent_look_up_symbols (objfile);
 }
 
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index d7a9b469ef8..7fd512a8ca8 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -2537,6 +2537,8 @@ arm_exidx_new_objfile (struct objfile *objfile)
   bfd_vma exidx_vma = 0, extab_vma = 0;
   LONGEST i;
 
+  gdb_assert (objfile != nullptr);
+
   /* If we've already touched this file, do nothing.  */
   if (arm_exidx_data_key.get (objfile->obfd.get ()) != nullptr)
     return;
diff --git a/gdb/auto-load.c b/gdb/auto-load.c
index b5fec13743c..8e0812f1c50 100644
--- a/gdb/auto-load.c
+++ b/gdb/auto-load.c
@@ -1201,6 +1201,8 @@ auto_load_section_scripts (struct objfile *objfile, const char *section_name)
 void
 load_auto_scripts_for_objfile (struct objfile *objfile)
 {
+  gdb_assert (objfile != nullptr);
+
   /* Return immediately if auto-loading has been globally disabled.
      This is to handle sequencing of operations during gdb startup.
      Also return immediately if OBJFILE was not created from a file
diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c
index bd45a2f2978..654263081e6 100644
--- a/gdb/linux-thread-db.c
+++ b/gdb/linux-thread-db.c
@@ -1274,6 +1274,8 @@ thread_db_new_objfile (struct objfile *objfile)
   /* This observer must always be called with inferior_ptid set
      correctly.  */
 
+  gdb_assert (objfile != nullptr);
+
   if (/* libpthread with separate debug info has its debug info file already
 	 loaded (and notified without successful thread_db initialization)
 	 the time gdb::observers::new_objfile.notify is called for the library itself.
diff --git a/gdb/observable.h b/gdb/observable.h
index 89877950a3c..ebd3766a988 100644
--- a/gdb/observable.h
+++ b/gdb/observable.h
@@ -111,7 +111,8 @@ extern observable<solib &/* solib */> solib_loaded;
 extern observable<program_space *, const solib &/* solib */,
 		  bool /* still_in_use */, bool /* silent */> solib_unloaded;
 
-/* The symbol file specified by OBJFILE has been loaded.  */
+/* The symbol file specified by OBJFILE has been loaded.  OBJFILE will not
+   be NULL.  */
 extern observable<struct objfile */* objfile */> new_objfile;
 
 /*  All objfiles from PSPACE were removed.  */
diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c
index 76e3da9f620..f9deba82d4b 100644
--- a/gdb/python/py-inferior.c
+++ b/gdb/python/py-inferior.c
@@ -163,9 +163,8 @@ python_inferior_exit (struct inferior *inf)
     gdbpy_print_stack ();
 }
 
-/* Callback used to notify Python listeners about new objfiles loaded in the
-   inferior.  OBJFILE may be NULL which means that the objfile list has been
-   cleared (emptied).  */
+/* Callback used to notify Python listeners that OBJFILE has been loaded in
+   to the inferior, OBJFILE will not be NULL.  */
 
 static void
 python_new_objfile (struct objfile *objfile)
@@ -173,6 +172,7 @@ python_new_objfile (struct objfile *objfile)
   if (!gdb_python_initialized)
     return;
 
+  gdb_assert (objfile != nullptr);
   gdbpy_enter enter_py (objfile->arch ());
 
   if (emit_new_objfile_event (objfile) < 0)
diff --git a/gdb/remote.c b/gdb/remote.c
index 88b06e688bc..e76f1ca0c08 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -16228,6 +16228,7 @@ remote_objfile_changed_check_symbols (program_space *pspace)
 static void
 remote_new_objfile (struct objfile *objfile)
 {
+  gdb_assert (objfile != nullptr);
   remote_objfile_changed_check_symbols (objfile->pspace ());
 }
 
diff --git a/gdb/symfile.c b/gdb/symfile.c
index 44a9480d9d9..5eb137f3b39 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -2662,8 +2662,8 @@ reread_symbols (int from_tty)
     {
       clear_symtab_users (0);
 
-      /* The registry for each objfile was cleared and
-	 gdb::observers::new_objfile.notify (NULL) has been called by
+      /* The registry for each objfile was cleared and the
+	 all_objfiles_removed observer was notified by the call to
 	 clear_symtab_users above.  Notify the new files now.  */
       for (auto iter : new_objfiles)
 	gdb::observers::new_objfile.notify (iter);
diff --git a/gdb/symtab.c b/gdb/symtab.c
index cd3bf876551..444cf7dcb20 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -1700,6 +1700,7 @@ maintenance_print_symbol_cache_statistics (const char *args, int from_tty)
 static void
 symtab_new_objfile_observer (struct objfile *objfile)
 {
+  gdb_assert (objfile != nullptr);
   symbol_cache_flush (objfile->pspace ());
 }