Merge branch 'for-4.1/core-noarch' into for-linus
diff --git a/include/linux/module.h b/include/linux/module.h
index b653d7c..7232fde 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -344,6 +344,10 @@
unsigned long *ftrace_callsites;
#endif
+#ifdef CONFIG_LIVEPATCH
+ bool klp_alive;
+#endif
+
#ifdef CONFIG_MODULE_UNLOAD
/* What modules depend on me? */
struct list_head source_list;
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index d03d613..284e269 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -89,16 +89,28 @@
/* sets obj->mod if object is not vmlinux and module is found */
static void klp_find_object_module(struct klp_object *obj)
{
+ struct module *mod;
+
if (!klp_is_module(obj))
return;
mutex_lock(&module_mutex);
/*
- * We don't need to take a reference on the module here because we have
- * the klp_mutex, which is also taken by the module notifier. This
- * prevents any module from unloading until we release the klp_mutex.
+ * We do not want to block removal of patched modules and therefore
+ * we do not take a reference here. The patches are removed by
+ * a going module handler instead.
*/
- obj->mod = find_module(obj->name);
+ mod = find_module(obj->name);
+ /*
+ * Do not mess work of the module coming and going notifiers.
+ * Note that the patch might still be needed before the going handler
+ * is called. Module functions can be called even in the GOING state
+ * until mod->exit() finishes. This is especially important for
+ * patches that modify semantic of the functions.
+ */
+ if (mod && mod->klp_alive)
+ obj->mod = mod;
+
mutex_unlock(&module_mutex);
}
@@ -248,11 +260,12 @@
/* first, check if it's an exported symbol */
preempt_disable();
sym = find_symbol(name, NULL, NULL, true, true);
- preempt_enable();
if (sym) {
*addr = sym->value;
+ preempt_enable();
return 0;
}
+ preempt_enable();
/* otherwise check if it's in another .o within the patch module */
return klp_find_object_symbol(pmod->name, name, addr);
@@ -314,12 +327,12 @@
rcu_read_lock();
func = list_first_or_null_rcu(&ops->func_stack, struct klp_func,
stack_node);
- rcu_read_unlock();
-
if (WARN_ON_ONCE(!func))
- return;
+ goto unlock;
klp_arch_set_pc(regs, (unsigned long)func->new_func);
+unlock:
+ rcu_read_unlock();
}
static void klp_disable_func(struct klp_func *func)
@@ -700,7 +713,7 @@
func->state = KLP_DISABLED;
return kobject_init_and_add(&func->kobj, &klp_ktype_func,
- obj->kobj, func->old_name);
+ obj->kobj, "%s", func->old_name);
}
/* parts of the initialization that is done only when the object is loaded */
@@ -735,6 +748,7 @@
return -EINVAL;
obj->state = KLP_DISABLED;
+ obj->mod = NULL;
klp_find_object_module(obj);
@@ -776,7 +790,7 @@
patch->state = KLP_DISABLED;
ret = kobject_init_and_add(&patch->kobj, &klp_ktype_patch,
- klp_root_kobj, patch->mod->name);
+ klp_root_kobj, "%s", patch->mod->name);
if (ret)
goto unlock;
@@ -925,6 +939,15 @@
mutex_lock(&klp_mutex);
+ /*
+ * Each module has to know that the notifier has been called.
+ * We never know what module will get patched by a new patch.
+ */
+ if (action == MODULE_STATE_COMING)
+ mod->klp_alive = true;
+ else /* MODULE_STATE_GOING */
+ mod->klp_alive = false;
+
list_for_each_entry(patch, &klp_patches, list) {
for (obj = patch->objs; obj->funcs; obj++) {
if (!klp_is_module(obj) || strcmp(obj->name, mod->name))