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Diffstat (limited to 'kernel/module.c')
-rw-r--r--kernel/module.c55
1 files changed, 42 insertions, 13 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 1f85fd5c89d3..ed4ec9c30bd2 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2989,10 +2989,31 @@ static void do_mod_ctors(struct module *mod)
#endif
}
+/* For freeing module_init on success, in case kallsyms traversing */
+struct mod_initfree {
+ struct rcu_head rcu;
+ void *module_init;
+};
+
+static void do_free_init(struct rcu_head *head)
+{
+ struct mod_initfree *m = container_of(head, struct mod_initfree, rcu);
+ module_memfree(m->module_init);
+ kfree(m);
+}
+
/* This is where the real work happens */
static int do_init_module(struct module *mod)
{
int ret = 0;
+ struct mod_initfree *freeinit;
+
+ freeinit = kmalloc(sizeof(*freeinit), GFP_KERNEL);
+ if (!freeinit) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+ freeinit->module_init = mod->module_init;
/*
* We want to find out whether @mod uses async during init. Clear
@@ -3005,18 +3026,7 @@ static int do_init_module(struct module *mod)
if (mod->init != NULL)
ret = do_one_initcall(mod->init);
if (ret < 0) {
- /*
- * Init routine failed: abort. Try to protect us from
- * buggy refcounters.
- */
- mod->state = MODULE_STATE_GOING;
- synchronize_sched();
- module_put(mod);
- blocking_notifier_call_chain(&module_notify_list,
- MODULE_STATE_GOING, mod);
- free_module(mod);
- wake_up_all(&module_wq);
- return ret;
+ goto fail_free_freeinit;
}
if (ret > 0) {
pr_warn("%s: '%s'->init suspiciously returned %d, it should "
@@ -3062,15 +3072,34 @@ static int do_init_module(struct module *mod)
#endif
unset_module_init_ro_nx(mod);
module_arch_freeing_init(mod);
- module_memfree(mod->module_init);
mod->module_init = NULL;
mod->init_size = 0;
mod->init_ro_size = 0;
mod->init_text_size = 0;
+ /*
+ * We want to free module_init, but be aware that kallsyms may be
+ * walking this with preempt disabled. In all the failure paths,
+ * we call synchronize_rcu/synchronize_sched, but we don't want
+ * to slow down the success path, so use actual RCU here.
+ */
+ call_rcu(&freeinit->rcu, do_free_init);
mutex_unlock(&module_mutex);
wake_up_all(&module_wq);
return 0;
+
+fail_free_freeinit:
+ kfree(freeinit);
+fail:
+ /* Try to protect us from buggy refcounters. */
+ mod->state = MODULE_STATE_GOING;
+ synchronize_sched();
+ module_put(mod);
+ blocking_notifier_call_chain(&module_notify_list,
+ MODULE_STATE_GOING, mod);
+ free_module(mod);
+ wake_up_all(&module_wq);
+ return ret;
}
static int may_init_module(void)