module: tracking: Keep a record of tainted unloaded modules only

This ensures that no module record/or entry is added to the
unloaded_tainted_modules list if it does not carry a taint.

Reported-by: Alexey Dobriyan <[email protected]>
Fixes: 99bd995 ("module: Introduce module unload taint tracking")
Signed-off-by: Aaron Tomlin <[email protected]>
Acked-by: Luis Chamberlain <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: Aaron Tomlin

kernel/module/tracking.c

@@ -22,6 +22,9 @@ int try_add_tainted_module(struct module *mod)
 
 	module_assert_mutex_or_preempt();
 
+	if (!mod->taints)
+		goto out;
+
 	list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules, list,
 				lockdep_is_held(&module_mutex)) {
 		if (!strcmp(mod_taint->name, mod->name) &&