module: verify_export_symbols under the lock

[net-next-2.6.git] / kernel / module.c

diff --git a/kernel/module.c b/kernel/module.c
index 28450047852a7c3aa0ce73f90810f17ea41904fd..f99558e1945a9b9450dee8f31d41a5b5ce5561fd 100644 (file)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1571,6 +1571,8 @@ EXPORT_SYMBOL_GPL(__symbol_get);
 /*
  * Ensure that an exported symbol [global namespace] does not already exist
  * in the kernel or in some other module's exported symbol table.
+ *
+ * You must hold the module_mutex.
  */
 static int verify_export_symbols(struct module *mod)
 {
@@ -1592,14 +1594,7 @@ static int verify_export_symbols(struct module *mod)
 
        for (i = 0; i < ARRAY_SIZE(arr); i++) {
                for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
-                       const struct kernel_symbol *sym;
-
-                       /* Stopping preemption makes find_symbol safe. */
-                       preempt_disable();
-                       sym = find_symbol(s->name, &owner, NULL, true, false);
-                       preempt_enable();
-
-                       if (sym) {
+                       if (find_symbol(s->name, &owner, NULL, true, false)) {
                                printk(KERN_ERR
                                       "%s: exports duplicate symbol %s"
                                       " (owned by %s)\n",
@@ -2440,11 +2435,6 @@ static noinline struct module *load_module(void __user *umod,
                        goto cleanup;
        }
 
-        /* Find duplicate symbols */
-       err = verify_export_symbols(mod);
-       if (err < 0)
-               goto cleanup;
-
        /* Set up and sort exception table */
        mod->extable = section_objs(hdr, sechdrs, secstrings, "__ex_table",
                                    sizeof(*mod->extable), &mod->num_exentries);
@@ -2506,10 +2496,14 @@ static noinline struct module *load_module(void __user *umod,
        mutex_lock(&module_mutex);
        if (find_module(mod->name)) {
                err = -EEXIST;
-               /* This will also unlock the mutex */
-               goto already_exists;
+               goto unlock;
        }
 
+       /* Find duplicate symbols */
+       err = verify_export_symbols(mod);
+       if (err < 0)
+               goto unlock;
+
        list_add_rcu(&mod->list, &modules);
        mutex_unlock(&module_mutex);
 
@@ -2536,7 +2530,7 @@ static noinline struct module *load_module(void __user *umod,
        mutex_lock(&module_mutex);
        /* Unlink carefully: kallsyms could be walking list. */
        list_del_rcu(&mod->list);
- already_exists:
+ unlock:
        mutex_unlock(&module_mutex);
        synchronize_sched();
        module_arch_cleanup(mod);