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Livepatching changes for 5.17

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Merge tag 'livepatching-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching

Pull livepatching updates from Petr Mladek:

 - Correctly handle kobjects when a livepatch init fails

 - Avoid CPU hogging when searching for many livepatched symbols

 - Add livepatch API page into documentation

* tag 'livepatching-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
  livepatch: Avoid CPU hogging with cond_resched
  livepatch: Fix missing unlock on error in klp_enable_patch()
  livepatch: Fix kobject refcount bug on klp_init_patch_early failure path
  Documentation: livepatch: Add livepatch API page
This commit is contained in:
Linus Torvalds 2022-01-16 10:08:13 +02:00
commit 77dbd72b98
8 changed files with 54 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

29
kernel/livepatch/core.c
View file

@ -862,14 +862,11 @@ static void klp_init_object_early(struct klp_patch *patch,
list_add_tail(&obj->node, &patch->obj_list);
}
static int klp_init_patch_early(struct klp_patch *patch)
static void klp_init_patch_early(struct klp_patch *patch)
{
struct klp_object *obj;
struct klp_func *func;
if (!patch->objs)
return -EINVAL;
INIT_LIST_HEAD(&patch->list);
INIT_LIST_HEAD(&patch->obj_list);
kobject_init(&patch->kobj, &klp_ktype_patch);
@ -879,20 +876,12 @@ static int klp_init_patch_early(struct klp_patch *patch)
init_completion(&patch->finish);
klp_for_each_object_static(patch, obj) {
if (!obj->funcs)
return -EINVAL;
klp_init_object_early(patch, obj);
klp_for_each_func_static(obj, func) {
klp_init_func_early(obj, func);
}
}
if (!try_module_get(patch->mod))
return -ENODEV;
return 0;
}
static int klp_init_patch(struct klp_patch *patch)
@ -1024,10 +1013,17 @@ err:
int klp_enable_patch(struct klp_patch *patch)
{
int ret;
struct klp_object *obj;
if (!patch || !patch->mod)
if (!patch || !patch->mod || !patch->objs)
return -EINVAL;
klp_for_each_object_static(patch, obj) {
if (!obj->funcs)
return -EINVAL;
}
if (!is_livepatch_module(patch->mod)) {
pr_err("module %s is not marked as a livepatch module\n",
patch->mod->name);
@ -1051,12 +1047,13 @@ int klp_enable_patch(struct klp_patch *patch)
return -EINVAL;
}
ret = klp_init_patch_early(patch);
if (ret) {
if (!try_module_get(patch->mod)) {
mutex_unlock(&klp_mutex);
return ret;
return -ENODEV;
}
klp_init_patch_early(patch);
ret = klp_init_patch(patch);
if (ret)
goto err;

6
kernel/livepatch/shadow.c
View file

@ -272,12 +272,12 @@ void klp_shadow_free(void *obj, unsigned long id, klp_shadow_dtor_t dtor)
EXPORT_SYMBOL_GPL(klp_shadow_free);
/**
* klp_shadow_free_all() - detach and free all <*, id> shadow variables
* klp_shadow_free_all() - detach and free all <_, id> shadow variables
* @id: data identifier
* @dtor: custom callback that can be used to unregister the variable
* and/or free data that the shadow variable points to (optional)
*
* This function releases the memory for all <*, id> shadow variable
* This function releases the memory for all <_, id> shadow variable
* instances, callers should stop referencing them accordingly.
*/
void klp_shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor)
@ -288,7 +288,7 @@ void klp_shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor)
spin_lock_irqsave(&klp_shadow_lock, flags);
/* Delete all <*, id> from hash */
/* Delete all <_, id> from hash */
hash_for_each(klp_shadow_hash, i, shadow, node) {
if (klp_shadow_match(shadow, shadow->obj, id))
klp_shadow_free_struct(shadow, dtor);