diff options
| -rw-r--r-- | include/linux/kthread.h | 1 | ||||
| -rw-r--r-- | include/linux/sched.h | 7 | ||||
| -rw-r--r-- | kernel/kthread.c | 20 | ||||
| -rw-r--r-- | kernel/sched/core.c | 36 | ||||
| -rw-r--r-- | kernel/workqueue.c | 6 |
5 files changed, 52 insertions, 18 deletions
diff --git a/include/linux/kthread.h b/include/linux/kthread.h index 13d55206ccf6..869b21dcf503 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -38,6 +38,7 @@ struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data), }) void kthread_bind(struct task_struct *k, unsigned int cpu); +void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask); int kthread_stop(struct task_struct *k); bool kthread_should_stop(void); bool kthread_should_park(void); diff --git a/include/linux/sched.h b/include/linux/sched.h index 44dca5b35de6..81bb4577274b 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2203,13 +2203,6 @@ static inline void calc_load_enter_idle(void) { } static inline void calc_load_exit_idle(void) { } #endif /* CONFIG_NO_HZ_COMMON */ -#ifndef CONFIG_CPUMASK_OFFSTACK -static inline int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) -{ - return set_cpus_allowed_ptr(p, &new_mask); -} -#endif - /* * Do not use outside of architecture code which knows its limitations. * diff --git a/kernel/kthread.c b/kernel/kthread.c index 10e489c448fe..7c40a189becc 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -325,16 +325,30 @@ struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), } EXPORT_SYMBOL(kthread_create_on_node); -static void __kthread_bind(struct task_struct *p, unsigned int cpu, long state) +static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, long state) { - /* Must have done schedule() in kthread() before we set_task_cpu */ + unsigned long flags; + if (!wait_task_inactive(p, state)) { WARN_ON(1); return; } + /* It's safe because the task is inactive. */ - do_set_cpus_allowed(p, cpumask_of(cpu)); + raw_spin_lock_irqsave(&p->pi_lock, flags); + do_set_cpus_allowed(p, mask); p->flags |= PF_NO_SETAFFINITY; + raw_spin_unlock_irqrestore(&p->pi_lock, flags); +} + +static void __kthread_bind(struct task_struct *p, unsigned int cpu, long state) +{ + __kthread_bind_mask(p, cpumask_of(cpu), state); +} + +void kthread_bind_mask(struct task_struct *p, const struct cpumask *mask) +{ + __kthread_bind_mask(p, mask, TASK_UNINTERRUPTIBLE); } /** diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ea6d74345e60..2e3b983da836 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1153,6 +1153,8 @@ static int migration_cpu_stop(void *data) void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) { + lockdep_assert_held(&p->pi_lock); + if (p->sched_class->set_cpus_allowed) p->sched_class->set_cpus_allowed(p, new_mask); @@ -1169,7 +1171,8 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) * task must not exit() & deallocate itself prematurely. The * call is not atomic; no spinlocks may be held. */ -int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) +static int __set_cpus_allowed_ptr(struct task_struct *p, + const struct cpumask *new_mask, bool check) { unsigned long flags; struct rq *rq; @@ -1178,6 +1181,15 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) rq = task_rq_lock(p, &flags); + /* + * Must re-check here, to close a race against __kthread_bind(), + * sched_setaffinity() is not guaranteed to observe the flag. + */ + if (check && (p->flags & PF_NO_SETAFFINITY)) { + ret = -EINVAL; + goto out; + } + if (cpumask_equal(&p->cpus_allowed, new_mask)) goto out; @@ -1214,6 +1226,11 @@ out: return ret; } + +int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) +{ + return __set_cpus_allowed_ptr(p, new_mask, false); +} EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); void set_task_cpu(struct task_struct *p, unsigned int new_cpu) @@ -1595,6 +1612,15 @@ static void update_avg(u64 *avg, u64 sample) s64 diff = sample - *avg; *avg += diff >> 3; } + +#else + +static inline int __set_cpus_allowed_ptr(struct task_struct *p, + const struct cpumask *new_mask, bool check) +{ + return set_cpus_allowed_ptr(p, new_mask); +} + #endif /* CONFIG_SMP */ static void @@ -4340,7 +4366,7 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) } #endif again: - retval = set_cpus_allowed_ptr(p, new_mask); + retval = __set_cpus_allowed_ptr(p, new_mask, true); if (!retval) { cpuset_cpus_allowed(p, cpus_allowed); @@ -4865,7 +4891,8 @@ void init_idle(struct task_struct *idle, int cpu) struct rq *rq = cpu_rq(cpu); unsigned long flags; - raw_spin_lock_irqsave(&rq->lock, flags); + raw_spin_lock_irqsave(&idle->pi_lock, flags); + raw_spin_lock(&rq->lock); __sched_fork(0, idle); idle->state = TASK_RUNNING; @@ -4891,7 +4918,8 @@ void init_idle(struct task_struct *idle, int cpu) #if defined(CONFIG_SMP) idle->on_cpu = 1; #endif - raw_spin_unlock_irqrestore(&rq->lock, flags); + raw_spin_unlock(&rq->lock); + raw_spin_unlock_irqrestore(&idle->pi_lock, flags); /* Set the preempt count _outside_ the spinlocks! */ init_idle_preempt_count(idle, cpu); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 4c4f06176f74..f5782d5fd196 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1714,9 +1714,7 @@ static struct worker *create_worker(struct worker_pool *pool) goto fail; set_user_nice(worker->task, pool->attrs->nice); - - /* prevent userland from meddling with cpumask of workqueue workers */ - worker->task->flags |= PF_NO_SETAFFINITY; + kthread_bind_mask(worker->task, pool->attrs->cpumask); /* successful, attach the worker to the pool */ worker_attach_to_pool(worker, pool); @@ -3856,7 +3854,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, } wq->rescuer = rescuer; - rescuer->task->flags |= PF_NO_SETAFFINITY; + kthread_bind_mask(rescuer->task, cpu_possible_mask); wake_up_process(rescuer->task); } |