diff options
| -rw-r--r-- | Documentation/livepatch/livepatch.txt | 3 | ||||
| -rw-r--r-- | kernel/livepatch/transition.c | 16 |
2 files changed, 15 insertions, 4 deletions
diff --git a/Documentation/livepatch/livepatch.txt b/Documentation/livepatch/livepatch.txt index 71d7f286ec4d..407e0f03dc99 100644 --- a/Documentation/livepatch/livepatch.txt +++ b/Documentation/livepatch/livepatch.txt @@ -163,7 +163,8 @@ patched state. This may be harmful to the system though. Writing 1 to the attribute sends a fake signal to all remaining blocking tasks. No proper signal is actually delivered (there is no data in signal pending structures). Tasks are interrupted or woken up, and forced to change -their patched state. +their patched state. Despite the sysfs attribute the fake signal is also sent +every 15 seconds automatically. Administrator can also affect a transition through /sys/kernel/livepatch/<patch>/force attribute. Writing 1 there clears diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index 300273819674..ea7697bb753e 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -29,10 +29,14 @@ #define MAX_STACK_ENTRIES 100 #define STACK_ERR_BUF_SIZE 128 +#define SIGNALS_TIMEOUT 15 + struct klp_patch *klp_transition_patch; static int klp_target_state = KLP_UNDEFINED; +static unsigned int klp_signals_cnt; + /* * This work can be performed periodically to finish patching or unpatching any * "straggler" tasks which failed to transition in the first attempt. @@ -393,6 +397,10 @@ void klp_try_complete_transition(void) put_online_cpus(); if (!complete) { + if (klp_signals_cnt && !(klp_signals_cnt % SIGNALS_TIMEOUT)) + klp_send_signals(); + klp_signals_cnt++; + /* * Some tasks weren't able to be switched over. Try again * later and/or wait for other methods like kernel exit @@ -454,6 +462,8 @@ void klp_start_transition(void) if (task->patch_state != klp_target_state) set_tsk_thread_flag(task, TIF_PATCH_PENDING); } + + klp_signals_cnt = 0; } /* @@ -578,14 +588,14 @@ void klp_copy_process(struct task_struct *child) /* * Sends a fake signal to all non-kthread tasks with TIF_PATCH_PENDING set. - * Kthreads with TIF_PATCH_PENDING set are woken up. Only admin can request this - * action currently. + * Kthreads with TIF_PATCH_PENDING set are woken up. */ void klp_send_signals(void) { struct task_struct *g, *task; - pr_notice("signaling remaining tasks\n"); + if (klp_signals_cnt == SIGNALS_TIMEOUT) + pr_notice("signaling remaining tasks\n"); read_lock(&tasklist_lock); for_each_process_thread(g, task) { |