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Diffstat (limited to 'kernel')
-rw-r--r--kernel/module.c77
1 files changed, 39 insertions, 38 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 2b2845ae983e..a9020bdd4cf6 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -98,6 +98,10 @@ DEFINE_MUTEX(module_mutex);
EXPORT_SYMBOL_GPL(module_mutex);
static LIST_HEAD(modules);
+/* Work queue for freeing init sections in success case */
+static struct work_struct init_free_wq;
+static struct llist_head init_free_list;
+
#ifdef CONFIG_MODULES_TREE_LOOKUP
/*
@@ -1949,6 +1953,8 @@ void module_enable_ro(const struct module *mod, bool after_init)
if (!rodata_enabled)
return;
+ set_vm_flush_reset_perms(mod->core_layout.base);
+ set_vm_flush_reset_perms(mod->init_layout.base);
frob_text(&mod->core_layout, set_memory_ro);
frob_text(&mod->core_layout, set_memory_x);
@@ -1972,15 +1978,6 @@ static void module_enable_nx(const struct module *mod)
frob_writable_data(&mod->init_layout, set_memory_nx);
}
-static void module_disable_nx(const struct module *mod)
-{
- frob_rodata(&mod->core_layout, set_memory_x);
- frob_ro_after_init(&mod->core_layout, set_memory_x);
- frob_writable_data(&mod->core_layout, set_memory_x);
- frob_rodata(&mod->init_layout, set_memory_x);
- frob_writable_data(&mod->init_layout, set_memory_x);
-}
-
/* Iterate through all modules and set each module's text as RW */
void set_all_modules_text_rw(void)
{
@@ -2024,23 +2021,8 @@ void set_all_modules_text_ro(void)
}
mutex_unlock(&module_mutex);
}
-
-static void disable_ro_nx(const struct module_layout *layout)
-{
- if (rodata_enabled) {
- frob_text(layout, set_memory_rw);
- frob_rodata(layout, set_memory_rw);
- frob_ro_after_init(layout, set_memory_rw);
- }
- frob_rodata(layout, set_memory_x);
- frob_ro_after_init(layout, set_memory_x);
- frob_writable_data(layout, set_memory_x);
-}
-
#else
-static void disable_ro_nx(const struct module_layout *layout) { }
static void module_enable_nx(const struct module *mod) { }
-static void module_disable_nx(const struct module *mod) { }
#endif
#ifdef CONFIG_LIVEPATCH
@@ -2120,6 +2102,11 @@ static void free_module_elf(struct module *mod)
void __weak module_memfree(void *module_region)
{
+ /*
+ * This memory may be RO, and freeing RO memory in an interrupt is not
+ * supported by vmalloc.
+ */
+ WARN_ON(in_interrupt());
vfree(module_region);
}
@@ -2171,7 +2158,6 @@ static void free_module(struct module *mod)
mutex_unlock(&module_mutex);
/* This may be empty, but that's OK */
- disable_ro_nx(&mod->init_layout);
module_arch_freeing_init(mod);
module_memfree(mod->init_layout.base);
kfree(mod->args);
@@ -2181,7 +2167,6 @@ static void free_module(struct module *mod)
lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size);
/* Finally, free the core (containing the module structure) */
- disable_ro_nx(&mod->core_layout);
module_memfree(mod->core_layout.base);
}
@@ -3420,17 +3405,34 @@ static void do_mod_ctors(struct module *mod)
/* For freeing module_init on success, in case kallsyms traversing */
struct mod_initfree {
- struct rcu_head rcu;
+ struct llist_node node;
void *module_init;
};
-static void do_free_init(struct rcu_head *head)
+static void do_free_init(struct work_struct *w)
{
- struct mod_initfree *m = container_of(head, struct mod_initfree, rcu);
- module_memfree(m->module_init);
- kfree(m);
+ struct llist_node *pos, *n, *list;
+ struct mod_initfree *initfree;
+
+ list = llist_del_all(&init_free_list);
+
+ synchronize_rcu();
+
+ llist_for_each_safe(pos, n, list) {
+ initfree = container_of(pos, struct mod_initfree, node);
+ module_memfree(initfree->module_init);
+ kfree(initfree);
+ }
}
+static int __init modules_wq_init(void)
+{
+ INIT_WORK(&init_free_wq, do_free_init);
+ init_llist_head(&init_free_list);
+ return 0;
+}
+module_init(modules_wq_init);
+
/*
* This is where the real work happens.
*
@@ -3507,7 +3509,6 @@ static noinline int do_init_module(struct module *mod)
#endif
module_enable_ro(mod, true);
mod_tree_remove_init(mod);
- disable_ro_nx(&mod->init_layout);
module_arch_freeing_init(mod);
mod->init_layout.base = NULL;
mod->init_layout.size = 0;
@@ -3518,14 +3519,18 @@ static noinline int do_init_module(struct module *mod)
* 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(), but we don't want to slow down the success
- * path, so use actual RCU here.
+ * path. module_memfree() cannot be called in an interrupt, so do the
+ * work and call synchronize_rcu() in a work queue.
+ *
* Note that module_alloc() on most architectures creates W+X page
* mappings which won't be cleaned up until do_free_init() runs. Any
* code such as mark_rodata_ro() which depends on those mappings to
* be cleaned up needs to sync with the queued work - ie
* rcu_barrier()
*/
- call_rcu(&freeinit->rcu, do_free_init);
+ if (llist_add(&freeinit->node, &init_free_list))
+ schedule_work(&init_free_wq);
+
mutex_unlock(&module_mutex);
wake_up_all(&module_wq);
@@ -3822,10 +3827,6 @@ static int load_module(struct load_info *info, const char __user *uargs,
module_bug_cleanup(mod);
mutex_unlock(&module_mutex);
- /* we can't deallocate the module until we clear memory protection */
- module_disable_ro(mod);
- module_disable_nx(mod);
-
ddebug_cleanup:
ftrace_release_mod(mod);
dynamic_debug_remove(mod, info->debug);