diff options
| -rw-r--r-- | kernel/module.c | 55 |
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) |