diff options
Diffstat (limited to 'kernel/freezer.c')
| -rw-r--r-- | kernel/freezer.c | 41 |
1 files changed, 19 insertions, 22 deletions
diff --git a/kernel/freezer.c b/kernel/freezer.c index 4fad0e6fca..759006a9a9 100644 --- a/kernel/freezer.c +++ b/kernel/freezer.c @@ -71,7 +71,11 @@ bool __refrigerator(bool check_kthr_stop) for (;;) { bool freeze; + raw_spin_lock_irq(¤t->pi_lock); set_current_state(TASK_FROZEN); + /* unstale saved_state so that __thaw_task() will wake us up */ + current->saved_state = TASK_RUNNING; + raw_spin_unlock_irq(¤t->pi_lock); spin_lock_irq(&freezer_lock); freeze = freezing(current) && !(check_kthr_stop && kthread_should_stop()); @@ -129,6 +133,7 @@ static int __set_task_frozen(struct task_struct *p, void *arg) WARN_ON_ONCE(debug_locks && p->lockdep_depth); #endif + p->saved_state = p->__state; WRITE_ONCE(p->__state, TASK_FROZEN); return TASK_FROZEN; } @@ -170,42 +175,34 @@ bool freeze_task(struct task_struct *p) } /* - * The special task states (TASK_STOPPED, TASK_TRACED) keep their canonical - * state in p->jobctl. If either of them got a wakeup that was missed because - * TASK_FROZEN, then their canonical state reflects that and the below will - * refuse to restore the special state and instead issue the wakeup. + * Restore the saved_state before the task entered freezer. For typical task + * in the __refrigerator(), saved_state == TASK_RUNNING so nothing happens + * here. For tasks which were TASK_NORMAL | TASK_FREEZABLE, their initial state + * is restored unless they got an expected wakeup (see ttwu_state_match()). + * Returns 1 if the task state was restored. */ -static int __set_task_special(struct task_struct *p, void *arg) +static int __restore_freezer_state(struct task_struct *p, void *arg) { - unsigned int state = 0; + unsigned int state = p->saved_state; - if (p->jobctl & JOBCTL_TRACED) - state = TASK_TRACED; - - else if (p->jobctl & JOBCTL_STOPPED) - state = TASK_STOPPED; - - if (state) + if (state != TASK_RUNNING) { WRITE_ONCE(p->__state, state); + return 1; + } - return state; + return 0; } void __thaw_task(struct task_struct *p) { - unsigned long flags, flags2; + unsigned long flags; spin_lock_irqsave(&freezer_lock, flags); if (WARN_ON_ONCE(freezing(p))) goto unlock; - if (lock_task_sighand(p, &flags2)) { - /* TASK_FROZEN -> TASK_{STOPPED,TRACED} */ - bool ret = task_call_func(p, __set_task_special, NULL); - unlock_task_sighand(p, &flags2); - if (ret) - goto unlock; - } + if (!frozen(p) || task_call_func(p, __restore_freezer_state, NULL)) + goto unlock; wake_up_state(p, TASK_FROZEN); unlock: |