diff options
| -rw-r--r-- | kernel/livepatch/core.c | 48 | ||||
| -rw-r--r-- | kernel/livepatch/core.h | 1 | ||||
| -rw-r--r-- | kernel/livepatch/patch.c | 31 | ||||
| -rw-r--r-- | kernel/livepatch/patch.h | 1 | ||||
| -rw-r--r-- | kernel/livepatch/transition.c | 4 |
5 files changed, 76 insertions, 9 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index ecb7660f1d8b..113645ee86b6 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -611,11 +611,16 @@ static struct kobj_type klp_ktype_func = { .sysfs_ops = &kobj_sysfs_ops, }; -static void klp_free_funcs(struct klp_object *obj) +static void __klp_free_funcs(struct klp_object *obj, bool nops_only) { struct klp_func *func, *tmp_func; klp_for_each_func_safe(obj, func, tmp_func) { + if (nops_only && !func->nop) + continue; + + list_del(&func->node); + /* Might be called from klp_init_patch() error path. */ if (func->kobj_added) { kobject_put(&func->kobj); @@ -640,12 +645,17 @@ static void klp_free_object_loaded(struct klp_object *obj) } } -static void klp_free_objects(struct klp_patch *patch) +static void __klp_free_objects(struct klp_patch *patch, bool nops_only) { struct klp_object *obj, *tmp_obj; klp_for_each_object_safe(patch, obj, tmp_obj) { - klp_free_funcs(obj); + __klp_free_funcs(obj, nops_only); + + if (nops_only && !obj->dynamic) + continue; + + list_del(&obj->node); /* Might be called from klp_init_patch() error path. */ if (obj->kobj_added) { @@ -656,6 +666,16 @@ static void klp_free_objects(struct klp_patch *patch) } } +static void klp_free_objects(struct klp_patch *patch) +{ + __klp_free_objects(patch, false); +} + +static void klp_free_objects_dynamic(struct klp_patch *patch) +{ + __klp_free_objects(patch, true); +} + /* * This function implements the free operations that can be called safely * under klp_mutex. @@ -1085,6 +1105,28 @@ void klp_discard_replaced_patches(struct klp_patch *new_patch) } /* + * This function removes the dynamically allocated 'nop' functions. + * + * We could be pretty aggressive. NOPs do not change the existing + * behavior except for adding unnecessary delay by the ftrace handler. + * + * It is safe even when the transition was forced. The ftrace handler + * will see a valid ops->func_stack entry thanks to RCU. + * + * We could even free the NOPs structures. They must be the last entry + * in ops->func_stack. Therefore unregister_ftrace_function() is called. + * It does the same as klp_synchronize_transition() to make sure that + * nobody is inside the ftrace handler once the operation finishes. + * + * IMPORTANT: It must be called right after removing the replaced patches! + */ +void klp_discard_nops(struct klp_patch *new_patch) +{ + klp_unpatch_objects_dynamic(klp_transition_patch); + klp_free_objects_dynamic(klp_transition_patch); +} + +/* * Remove parts of patches that touch a given kernel module. The list of * patches processed might be limited. When limit is NULL, all patches * will be handled. diff --git a/kernel/livepatch/core.h b/kernel/livepatch/core.h index f6a853adcc00..e6200f38701f 100644 --- a/kernel/livepatch/core.h +++ b/kernel/livepatch/core.h @@ -9,6 +9,7 @@ extern struct list_head klp_patches; void klp_free_patch_start(struct klp_patch *patch); void klp_discard_replaced_patches(struct klp_patch *new_patch); +void klp_discard_nops(struct klp_patch *new_patch); static inline bool klp_is_object_loaded(struct klp_object *obj) { diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c index 0ff466ab4b5a..99cb3ad05eb4 100644 --- a/kernel/livepatch/patch.c +++ b/kernel/livepatch/patch.c @@ -246,15 +246,26 @@ err: return ret; } -void klp_unpatch_object(struct klp_object *obj) +static void __klp_unpatch_object(struct klp_object *obj, bool nops_only) { struct klp_func *func; - klp_for_each_func(obj, func) + klp_for_each_func(obj, func) { + if (nops_only && !func->nop) + continue; + if (func->patched) klp_unpatch_func(func); + } - obj->patched = false; + if (obj->dynamic || !nops_only) + obj->patched = false; +} + + +void klp_unpatch_object(struct klp_object *obj) +{ + __klp_unpatch_object(obj, false); } int klp_patch_object(struct klp_object *obj) @@ -277,11 +288,21 @@ int klp_patch_object(struct klp_object *obj) return 0; } -void klp_unpatch_objects(struct klp_patch *patch) +static void __klp_unpatch_objects(struct klp_patch *patch, bool nops_only) { struct klp_object *obj; klp_for_each_object(patch, obj) if (obj->patched) - klp_unpatch_object(obj); + __klp_unpatch_object(obj, nops_only); +} + +void klp_unpatch_objects(struct klp_patch *patch) +{ + __klp_unpatch_objects(patch, false); +} + +void klp_unpatch_objects_dynamic(struct klp_patch *patch) +{ + __klp_unpatch_objects(patch, true); } diff --git a/kernel/livepatch/patch.h b/kernel/livepatch/patch.h index a9b16e513656..d5f2fbe373e0 100644 --- a/kernel/livepatch/patch.h +++ b/kernel/livepatch/patch.h @@ -30,5 +30,6 @@ struct klp_ops *klp_find_ops(void *old_func); int klp_patch_object(struct klp_object *obj); void klp_unpatch_object(struct klp_object *obj); void klp_unpatch_objects(struct klp_patch *patch); +void klp_unpatch_objects_dynamic(struct klp_patch *patch); #endif /* _LIVEPATCH_PATCH_H */ diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index f4c5908a9731..300273819674 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -85,8 +85,10 @@ static void klp_complete_transition(void) klp_transition_patch->mod->name, klp_target_state == KLP_PATCHED ? "patching" : "unpatching"); - if (klp_transition_patch->replace && klp_target_state == KLP_PATCHED) + if (klp_transition_patch->replace && klp_target_state == KLP_PATCHED) { klp_discard_replaced_patches(klp_transition_patch); + klp_discard_nops(klp_transition_patch); + } if (klp_target_state == KLP_UNPATCHED) { /* |