Livepatching changes for 6.1

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Merge tag 'livepatching-for-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching

Pull livepatching updates from Petr Mladek:

 - Fix race between fork and livepatch transition revert

 - Add sysfs entry that shows "patched" state for each object (module)
   that can be livepatched by the given livepatch

 - Some clean up

* tag 'livepatching-for-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
  selftests/livepatch: add sysfs test
  livepatch: add sysfs entry "patched" for each klp_object
  selftests/livepatch: normalize sysctl error message
  livepatch: Add a missing newline character in klp_module_coming()
  livepatch: fix race between fork and KLP transition
This commit is contained in:
Linus Torvalds 2022-10-10 11:36:19 -07:00
commit 4de65c5830
6 changed files with 166 additions and 5 deletions

View file

@ -325,6 +325,7 @@ int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
* /sys/kernel/livepatch/<patch>/transition
* /sys/kernel/livepatch/<patch>/force
* /sys/kernel/livepatch/<patch>/<object>
* /sys/kernel/livepatch/<patch>/<object>/patched
* /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
*/
static int __klp_disable_patch(struct klp_patch *patch);
@ -431,6 +432,22 @@ static struct attribute *klp_patch_attrs[] = {
};
ATTRIBUTE_GROUPS(klp_patch);
static ssize_t patched_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct klp_object *obj;
obj = container_of(kobj, struct klp_object, kobj);
return sysfs_emit(buf, "%d\n", obj->patched);
}
static struct kobj_attribute patched_kobj_attr = __ATTR_RO(patched);
static struct attribute *klp_object_attrs[] = {
&patched_kobj_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(klp_object);
static void klp_free_object_dynamic(struct klp_object *obj)
{
kfree(obj->name);
@ -576,6 +593,7 @@ static void klp_kobj_release_object(struct kobject *kobj)
static struct kobj_type klp_ktype_object = {
.release = klp_kobj_release_object,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = klp_object_groups,
};
static void klp_kobj_release_func(struct kobject *kobj)
@ -1171,7 +1189,7 @@ int klp_module_coming(struct module *mod)
return -EINVAL;
if (!strcmp(mod->name, "vmlinux")) {
pr_err("vmlinux.ko: invalid module name");
pr_err("vmlinux.ko: invalid module name\n");
return -EINVAL;
}

View file

@ -610,9 +610,23 @@ void klp_reverse_transition(void)
/* Called from copy_process() during fork */
void klp_copy_process(struct task_struct *child)
{
child->patch_state = current->patch_state;
/* TIF_PATCH_PENDING gets copied in setup_thread_stack() */
/*
* The parent process may have gone through a KLP transition since
* the thread flag was copied in setup_thread_stack earlier. Bring
* the task flag up to date with the parent here.
*
* The operation is serialized against all klp_*_transition()
* operations by the tasklist_lock. The only exception is
* klp_update_patch_state(current), but we cannot race with
* that because we are current.
*/
if (test_tsk_thread_flag(current, TIF_PATCH_PENDING))
set_tsk_thread_flag(child, TIF_PATCH_PENDING);
else
clear_tsk_thread_flag(child, TIF_PATCH_PENDING);
child->patch_state = current->patch_state;
}
/*