module: set nx before marking module MODULE_STATE_COMING.

We currently set RO & NX on modules very late: after we move them from
MODULE_STATE_UNFORMED to MODULE_STATE_COMING, and after we call
parse_args() (which can exec code in the module).

Much better is to do it in complete_formation() and then call
the notifier.

This means that the notifiers will be called on a module which
is already RO & NX, so that may cause problems (ftrace already
changed so they're unaffected).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/kernel/module.c b/kernel/module.c
index 66e4e0d..f944c72 100644 (file)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3023,21 +3023,6 @@ static int do_init_module(struct module *mod)
         */
        current->flags &= ~PF_USED_ASYNC;
 
-       blocking_notifier_call_chain(&module_notify_list,
-                       MODULE_STATE_COMING, mod);
-
-       /* Set RO and NX regions for core */
-       set_section_ro_nx(mod->module_core,
-                               mod->core_text_size,
-                               mod->core_ro_size,
-                               mod->core_size);
-
-       /* Set RO and NX regions for init */
-       set_section_ro_nx(mod->module_init,
-                               mod->init_text_size,
-                               mod->init_ro_size,
-                               mod->init_size);
-
        do_mod_ctors(mod);
        /* Start the module */
        if (mod->init != NULL)
@@ -3168,9 +3153,26 @@ static int complete_formation(struct module *mod, struct load_info *info)
        /* This relies on module_mutex for list integrity. */
        module_bug_finalize(info->hdr, info->sechdrs, mod);
 
+       /* Set RO and NX regions for core */
+       set_section_ro_nx(mod->module_core,
+                               mod->core_text_size,
+                               mod->core_ro_size,
+                               mod->core_size);
+
+       /* Set RO and NX regions for init */
+       set_section_ro_nx(mod->module_init,
+                               mod->init_text_size,
+                               mod->init_ro_size,
+                               mod->init_size);
+
        /* Mark state as coming so strong_try_module_get() ignores us,
         * but kallsyms etc. can see us. */
        mod->state = MODULE_STATE_COMING;
+       mutex_unlock(&module_mutex);
+
+       blocking_notifier_call_chain(&module_notify_list,
+                                    MODULE_STATE_COMING, mod);
+       return 0;
 
 out:
        mutex_unlock(&module_mutex);