Module: check to see if we have a built in module with the same name

When trying to load a module with the same name as a built-in one, a
scary kobject backtrace comes up.  Prevent that from checking for this
condition and warning the user as to what exactly is going on.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/kernel/module.c b/kernel/module.c
index 1bb4c5e..76ddc85 100644 (file)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1214,6 +1214,7 @@ void module_remove_modinfo_attrs(struct module *mod)
 int mod_sysfs_init(struct module *mod)
 {
        int err;
+       struct kobject *kobj;
 
        if (!module_sysfs_initialized) {
                printk(KERN_ERR "%s: module sysfs not initialized\n",
@@ -1221,6 +1222,15 @@ int mod_sysfs_init(struct module *mod)
                err = -EINVAL;
                goto out;
        }
+
+       kobj = kset_find_obj(module_kset, mod->name);
+       if (kobj) {
+               printk(KERN_ERR "%s: module is already loaded\n", mod->name);
+               kobject_put(kobj);
+               err = -EINVAL;
+               goto out;
+       }
+
        mod->mkobj.mod = mod;
 
        memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj));