diff options
| -rw-r--r-- | kernel/sched/core.c | 36 | ||||
| -rw-r--r-- | kernel/sched/cputime.c | 3 | ||||
| -rw-r--r-- | kernel/sched/rt.c | 2 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 3 | ||||
| -rw-r--r-- | kernel/sched/wait.c | 16 |
5 files changed, 45 insertions, 15 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 4d568ac9319e..7063c6a07440 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1947,13 +1947,38 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) #ifdef CONFIG_SMP /* + * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be + * possible to, falsely, observe p->on_cpu == 0. + * + * One must be running (->on_cpu == 1) in order to remove oneself + * from the runqueue. + * + * [S] ->on_cpu = 1; [L] ->on_rq + * UNLOCK rq->lock + * RMB + * LOCK rq->lock + * [S] ->on_rq = 0; [L] ->on_cpu + * + * Pairs with the full barrier implied in the UNLOCK+LOCK on rq->lock + * from the consecutive calls to schedule(); the first switching to our + * task, the second putting it to sleep. + */ + smp_rmb(); + + /* * If the owning (remote) cpu is still in the middle of schedule() with * this task as prev, wait until its done referencing the task. */ while (p->on_cpu) cpu_relax(); /* - * Pairs with the smp_wmb() in finish_lock_switch(). + * Combined with the control dependency above, we have an effective + * smp_load_acquire() without the need for full barriers. + * + * Pairs with the smp_store_release() in finish_lock_switch(). + * + * This ensures that tasks getting woken will be fully ordered against + * their previous state and preserve Program Order. */ smp_rmb(); @@ -2039,7 +2064,6 @@ out: */ int wake_up_process(struct task_struct *p) { - WARN_ON(task_is_stopped_or_traced(p)); return try_to_wake_up(p, TASK_NORMAL, 0); } EXPORT_SYMBOL(wake_up_process); @@ -5847,13 +5871,13 @@ static int init_rootdomain(struct root_domain *rd) { memset(rd, 0, sizeof(*rd)); - if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) + if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL)) goto out; - if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) + if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL)) goto free_span; - if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) + if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) goto free_online; - if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) + if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) goto free_dlo_mask; init_dl_bw(&rd->dl_bw); diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 26a54461bf59..05de80b48586 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -788,6 +788,9 @@ cputime_t task_gtime(struct task_struct *t) unsigned int seq; cputime_t gtime; + if (!context_tracking_is_enabled()) + return t->gtime; + do { seq = read_seqbegin(&t->vtime_seqlock); diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index e3cc16312046..8ec86abe0ea1 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -64,7 +64,7 @@ static void start_rt_bandwidth(struct rt_bandwidth *rt_b) raw_spin_unlock(&rt_b->rt_runtime_lock); } -#ifdef CONFIG_SMP +#if defined(CONFIG_SMP) && defined(HAVE_RT_PUSH_IPI) static void push_irq_work_func(struct irq_work *work); #endif diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index efd3bfc7e347..b242775bf670 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1073,6 +1073,9 @@ static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) * We must ensure this doesn't happen until the switch is completely * finished. * + * In particular, the load of prev->state in finish_task_switch() must + * happen before this. + * * Pairs with the control dependency and rmb in try_to_wake_up(). */ smp_store_release(&prev->on_cpu, 0); diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 052e02672d12..f10bd873e684 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -583,18 +583,18 @@ EXPORT_SYMBOL(wake_up_atomic_t); __sched int bit_wait(struct wait_bit_key *word) { - if (signal_pending_state(current->state, current)) - return 1; schedule(); + if (signal_pending(current)) + return -EINTR; return 0; } EXPORT_SYMBOL(bit_wait); __sched int bit_wait_io(struct wait_bit_key *word) { - if (signal_pending_state(current->state, current)) - return 1; io_schedule(); + if (signal_pending(current)) + return -EINTR; return 0; } EXPORT_SYMBOL(bit_wait_io); @@ -602,11 +602,11 @@ EXPORT_SYMBOL(bit_wait_io); __sched int bit_wait_timeout(struct wait_bit_key *word) { unsigned long now = READ_ONCE(jiffies); - if (signal_pending_state(current->state, current)) - return 1; if (time_after_eq(now, word->timeout)) return -EAGAIN; schedule_timeout(word->timeout - now); + if (signal_pending(current)) + return -EINTR; return 0; } EXPORT_SYMBOL_GPL(bit_wait_timeout); @@ -614,11 +614,11 @@ EXPORT_SYMBOL_GPL(bit_wait_timeout); __sched int bit_wait_io_timeout(struct wait_bit_key *word) { unsigned long now = READ_ONCE(jiffies); - if (signal_pending_state(current->state, current)) - return 1; if (time_after_eq(now, word->timeout)) return -EAGAIN; io_schedule_timeout(word->timeout - now); + if (signal_pending(current)) + return -EINTR; return 0; } EXPORT_SYMBOL_GPL(bit_wait_io_timeout); |