diff options
Diffstat (limited to 'kernel/livepatch/transition.c')
| -rw-r--r-- | kernel/livepatch/transition.c | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index edcfcb8ebb2d..be5bfa533ee8 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -33,6 +33,8 @@ struct klp_patch *klp_transition_patch; static int klp_target_state = KLP_UNDEFINED; +static bool klp_forced = false; + /* * This work can be performed periodically to finish patching or unpatching any * "straggler" tasks which failed to transition in the first attempt. @@ -146,9 +148,12 @@ done: /* * See complementary comment in __klp_enable_patch() for why we * keep the module reference for immediate patches. + * + * klp_forced or immediate_func set implies unbounded increase of + * module's ref count if the module is disabled/enabled in a loop. */ - if (!klp_transition_patch->immediate && !immediate_func && - klp_target_state == KLP_UNPATCHED) { + if (!klp_forced && !klp_transition_patch->immediate && + !immediate_func && klp_target_state == KLP_UNPATCHED) { module_put(klp_transition_patch->mod); } @@ -649,3 +654,30 @@ void klp_send_signals(void) } read_unlock(&tasklist_lock); } + +/* + * Drop TIF_PATCH_PENDING of all tasks on admin's request. This forces an + * existing transition to finish. + * + * NOTE: klp_update_patch_state(task) requires the task to be inactive or + * 'current'. This is not the case here and the consistency model could be + * broken. Administrator, who is the only one to execute the + * klp_force_transitions(), has to be aware of this. + */ +void klp_force_transition(void) +{ + struct task_struct *g, *task; + unsigned int cpu; + + pr_warn("forcing remaining tasks to the patched state\n"); + + read_lock(&tasklist_lock); + for_each_process_thread(g, task) + klp_update_patch_state(task); + read_unlock(&tasklist_lock); + + for_each_possible_cpu(cpu) + klp_update_patch_state(idle_task(cpu)); + + klp_forced = true; +} |