[PATCH] implement print_modules()

From: Arjan van de Ven <arjanv@redhat.com>,
      Rusty Russell <rusty@rustcorp.com.au>

The patch below resolves the "Not Yet Implemented" print_modules() thing.
This is a really useful feature for distros; it allows us to do statistical
analysis on which modules are present how often in oopses compared to how
often they are used normally.  In addition it helps to spot candidates for
certain bugs without having to go back to the customer asking for this
information.

include/linux/module.h

@@ -24,7 +24,6 @@
 
 /* Not Yet Implemented */
 #define MODULE_SUPPORTED_DEVICE(name)
-#define print_modules()
 
 /* v850 toolchain uses a `_' prefix for all user symbols */
 #ifndef MODULE_SYMBOL_PREFIX
@@ -425,6 +424,7 @@ const struct exception_table_entry *search_module_extables(unsigned long addr);
 int register_module_notifier(struct notifier_block * nb);
 int unregister_module_notifier(struct notifier_block * nb);
 
+extern void print_modules(void);
 #else /* !CONFIG_MODULES... */
 #define EXPORT_SYMBOL(sym)
 #define EXPORT_SYMBOL_GPL(sym)
@@ -505,6 +505,9 @@ static inline int unregister_module_notifier(struct notifier_block * nb)
 
 #define module_put_and_exit(code) do_exit(code)
 
+static inline void print_modules(void)
+{
+}
 #endif /* CONFIG_MODULES */
 
 #define symbol_request(x) try_then_request_module(symbol_get(x), "symbol:" #x)

kernel/module.c

@@ -2040,6 +2040,17 @@ struct module *module_text_address(unsigned long addr)
 	return NULL;
 }
 
+/* Don't grab lock, we're oopsing. */
+void print_modules(void)
+{
+	struct module *mod;
+
+	printk("Modules linked in:");
+	list_for_each_entry(mod, &modules, list)
+		printk(" %s", mod->name);
+	printk("\n");
+}
+
 #ifdef CONFIG_MODVERSIONS
 /* Generate the signature for struct module here, too, for modversions. */
 void struct_module(struct module *mod) { return; }