module: fix memory leak when load fails after srcversion/version allocated

Normally the twisty paths of sysfs will free the attributes, but not if
we fail before we hook it into sysfs (which is the last thing we do in
load_module).

(This sysfs code is a turd, no doubt there are other issues lurking too).
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>

kernel/module.c

@@ -1797,6 +1797,17 @@ static void setup_modinfo(struct module *mod, Elf_Shdr *sechdrs,
 	}
 }
 
+static void free_modinfo(struct module *mod)
+{
+	struct module_attribute *attr;
+	int i;
+
+	for (i = 0; (attr = modinfo_attrs[i]); i++) {
+		if (attr->free)
+			attr->free(mod);
+	}
+}
+
 #ifdef CONFIG_KALLSYMS
 
 /* lookup symbol in given range of kernel_symbols */
@@ -2506,6 +2517,7 @@ static noinline struct module *load_module(void __user *umod,
 	synchronize_sched();
 	module_arch_cleanup(mod);
  cleanup:
+	free_modinfo(mod);
 	kobject_del(&mod->mkobj.kobj);
 	kobject_put(&mod->mkobj.kobj);
  free_unload: