aboutsummaryrefslogtreecommitdiffstats
path: root/kernel
diff options
context:
space:
mode:
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c104
-rw-r--r--kernel/exit.c16
-rw-r--r--kernel/fork.c20
-rw-r--r--kernel/kprobes.c6
-rw-r--r--kernel/sched/core.c19
-rw-r--r--kernel/sched/fair.c34
-rw-r--r--kernel/sched/rt.c5
-rw-r--r--kernel/watchdog.c2
8 files changed, 149 insertions, 57 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 32b48c889711..ba36013cfb21 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2300,6 +2300,9 @@ do { \
return div64_u64(dividend, divisor);
}
+static DEFINE_PER_CPU(int, perf_throttled_count);
+static DEFINE_PER_CPU(u64, perf_throttled_seq);
+
static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
{
struct hw_perf_event *hwc = &event->hw;
@@ -2325,16 +2328,29 @@ static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
}
}
-static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
+/*
+ * combine freq adjustment with unthrottling to avoid two passes over the
+ * events. At the same time, make sure, having freq events does not change
+ * the rate of unthrottling as that would introduce bias.
+ */
+static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
+ int needs_unthr)
{
struct perf_event *event;
struct hw_perf_event *hwc;
- u64 interrupts, now;
+ u64 now, period = TICK_NSEC;
s64 delta;
- if (!ctx->nr_freq)
+ /*
+ * only need to iterate over all events iff:
+ * - context have events in frequency mode (needs freq adjust)
+ * - there are events to unthrottle on this cpu
+ */
+ if (!(ctx->nr_freq || needs_unthr))
return;
+ raw_spin_lock(&ctx->lock);
+
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
if (event->state != PERF_EVENT_STATE_ACTIVE)
continue;
@@ -2344,13 +2360,8 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
hwc = &event->hw;
- interrupts = hwc->interrupts;
- hwc->interrupts = 0;
-
- /*
- * unthrottle events on the tick
- */
- if (interrupts == MAX_INTERRUPTS) {
+ if (needs_unthr && hwc->interrupts == MAX_INTERRUPTS) {
+ hwc->interrupts = 0;
perf_log_throttle(event, 1);
event->pmu->start(event, 0);
}
@@ -2358,14 +2369,26 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
if (!event->attr.freq || !event->attr.sample_freq)
continue;
- event->pmu->read(event);
+ /*
+ * stop the event and update event->count
+ */
+ event->pmu->stop(event, PERF_EF_UPDATE);
+
now = local64_read(&event->count);
delta = now - hwc->freq_count_stamp;
hwc->freq_count_stamp = now;
+ /*
+ * restart the event
+ * reload only if value has changed
+ */
if (delta > 0)
perf_adjust_period(event, period, delta);
+
+ event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
}
+
+ raw_spin_unlock(&ctx->lock);
}
/*
@@ -2388,16 +2411,13 @@ static void rotate_ctx(struct perf_event_context *ctx)
*/
static void perf_rotate_context(struct perf_cpu_context *cpuctx)
{
- u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC;
struct perf_event_context *ctx = NULL;
- int rotate = 0, remove = 1, freq = 0;
+ int rotate = 0, remove = 1;
if (cpuctx->ctx.nr_events) {
remove = 0;
if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
rotate = 1;
- if (cpuctx->ctx.nr_freq)
- freq = 1;
}
ctx = cpuctx->task_ctx;
@@ -2405,37 +2425,26 @@ static void perf_rotate_context(struct perf_cpu_context *cpuctx)
remove = 0;
if (ctx->nr_events != ctx->nr_active)
rotate = 1;
- if (ctx->nr_freq)
- freq = 1;
}
- if (!rotate && !freq)
+ if (!rotate)
goto done;
perf_ctx_lock(cpuctx, cpuctx->task_ctx);
perf_pmu_disable(cpuctx->ctx.pmu);
- if (freq) {
- perf_ctx_adjust_freq(&cpuctx->ctx, interval);
- if (ctx)
- perf_ctx_adjust_freq(ctx, interval);
- }
-
- if (rotate) {
- cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
- if (ctx)
- ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
+ cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
+ if (ctx)
+ ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
- rotate_ctx(&cpuctx->ctx);
- if (ctx)
- rotate_ctx(ctx);
+ rotate_ctx(&cpuctx->ctx);
+ if (ctx)
+ rotate_ctx(ctx);
- perf_event_sched_in(cpuctx, ctx, current);
- }
+ perf_event_sched_in(cpuctx, ctx, current);
perf_pmu_enable(cpuctx->ctx.pmu);
perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
-
done:
if (remove)
list_del_init(&cpuctx->rotation_list);
@@ -2445,10 +2454,22 @@ void perf_event_task_tick(void)
{
struct list_head *head = &__get_cpu_var(rotation_list);
struct perf_cpu_context *cpuctx, *tmp;
+ struct perf_event_context *ctx;
+ int throttled;
WARN_ON(!irqs_disabled());
+ __this_cpu_inc(perf_throttled_seq);
+ throttled = __this_cpu_xchg(perf_throttled_count, 0);
+
list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
+ ctx = &cpuctx->ctx;
+ perf_adjust_freq_unthr_context(ctx, throttled);
+
+ ctx = cpuctx->task_ctx;
+ if (ctx)
+ perf_adjust_freq_unthr_context(ctx, throttled);
+
if (cpuctx->jiffies_interval == 1 ||
!(jiffies % cpuctx->jiffies_interval))
perf_rotate_context(cpuctx);
@@ -4509,6 +4530,7 @@ static int __perf_event_overflow(struct perf_event *event,
{
int events = atomic_read(&event->event_limit);
struct hw_perf_event *hwc = &event->hw;
+ u64 seq;
int ret = 0;
/*
@@ -4518,14 +4540,20 @@ static int __perf_event_overflow(struct perf_event *event,
if (unlikely(!is_sampling_event(event)))
return 0;
- if (unlikely(hwc->interrupts >= max_samples_per_tick)) {
- if (throttle) {
+ seq = __this_cpu_read(perf_throttled_seq);
+ if (seq != hwc->interrupts_seq) {
+ hwc->interrupts_seq = seq;
+ hwc->interrupts = 1;
+ } else {
+ hwc->interrupts++;
+ if (unlikely(throttle
+ && hwc->interrupts >= max_samples_per_tick)) {
+ __this_cpu_inc(perf_throttled_count);
hwc->interrupts = MAX_INTERRUPTS;
perf_log_throttle(event, 0);
ret = 1;
}
- } else
- hwc->interrupts++;
+ }
if (event->attr.freq) {
u64 now = perf_clock();
diff --git a/kernel/exit.c b/kernel/exit.c
index 294b1709170d..4b4042f9bc6a 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1038,6 +1038,22 @@ void do_exit(long code)
if (tsk->nr_dirtied)
__this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied);
exit_rcu();
+
+ /*
+ * The setting of TASK_RUNNING by try_to_wake_up() may be delayed
+ * when the following two conditions become true.
+ * - There is race condition of mmap_sem (It is acquired by
+ * exit_mm()), and
+ * - SMI occurs before setting TASK_RUNINNG.
+ * (or hypervisor of virtual machine switches to other guest)
+ * As a result, we may become TASK_RUNNING after becoming TASK_DEAD
+ *
+ * To avoid it, we have to wait for releasing tsk->pi_lock which
+ * is held by try_to_wake_up()
+ */
+ smp_mb();
+ raw_spin_unlock_wait(&tsk->pi_lock);
+
/* causes final put_task_struct in finish_task_switch(). */
tsk->state = TASK_DEAD;
tsk->flags |= PF_NOFREEZE; /* tell freezer to ignore us */
diff --git a/kernel/fork.c b/kernel/fork.c
index 051f090d40c1..1b2ef3c23ae4 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -647,6 +647,26 @@ struct mm_struct *get_task_mm(struct task_struct *task)
}
EXPORT_SYMBOL_GPL(get_task_mm);
+struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
+{
+ struct mm_struct *mm;
+ int err;
+
+ err = mutex_lock_killable(&task->signal->cred_guard_mutex);
+ if (err)
+ return ERR_PTR(err);
+
+ mm = get_task_mm(task);
+ if (mm && mm != current->mm &&
+ !ptrace_may_access(task, mode)) {
+ mmput(mm);
+ mm = ERR_PTR(-EACCES);
+ }
+ mutex_unlock(&task->signal->cred_guard_mutex);
+
+ return mm;
+}
+
/* Please note the differences between mmput and mm_release.
* mmput is called whenever we stop holding onto a mm_struct,
* error success whatever.
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 29f5b65bee29..9788c0ec6f43 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1673,8 +1673,12 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
ri->rp = rp;
ri->task = current;
- if (rp->entry_handler && rp->entry_handler(ri, regs))
+ if (rp->entry_handler && rp->entry_handler(ri, regs)) {
+ raw_spin_lock_irqsave(&rp->lock, flags);
+ hlist_add_head(&ri->hlist, &rp->free_instances);
+ raw_spin_unlock_irqrestore(&rp->lock, flags);
return 0;
+ }
arch_prepare_kretprobe(ri, regs);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index df00cb09263e..5255c9d2e053 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -74,6 +74,7 @@
#include <asm/tlb.h>
#include <asm/irq_regs.h>
+#include <asm/mutex.h>
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#endif
@@ -723,9 +724,6 @@ static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
p->sched_class->dequeue_task(rq, p, flags);
}
-/*
- * activate_task - move a task to the runqueue.
- */
void activate_task(struct rq *rq, struct task_struct *p, int flags)
{
if (task_contributes_to_load(p))
@@ -734,9 +732,6 @@ void activate_task(struct rq *rq, struct task_struct *p, int flags)
enqueue_task(rq, p, flags);
}
-/*
- * deactivate_task - remove a task from the runqueue.
- */
void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
{
if (task_contributes_to_load(p))
@@ -4134,7 +4129,7 @@ recheck:
on_rq = p->on_rq;
running = task_current(rq, p);
if (on_rq)
- deactivate_task(rq, p, 0);
+ dequeue_task(rq, p, 0);
if (running)
p->sched_class->put_prev_task(rq, p);
@@ -4147,7 +4142,7 @@ recheck:
if (running)
p->sched_class->set_curr_task(rq);
if (on_rq)
- activate_task(rq, p, 0);
+ enqueue_task(rq, p, 0);
check_class_changed(rq, p, prev_class, oldprio);
task_rq_unlock(rq, p, &flags);
@@ -4998,9 +4993,9 @@ static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
* placed properly.
*/
if (p->on_rq) {
- deactivate_task(rq_src, p, 0);
+ dequeue_task(rq_src, p, 0);
set_task_cpu(p, dest_cpu);
- activate_task(rq_dest, p, 0);
+ enqueue_task(rq_dest, p, 0);
check_preempt_curr(rq_dest, p, 0);
}
done:
@@ -7032,10 +7027,10 @@ static void normalize_task(struct rq *rq, struct task_struct *p)
on_rq = p->on_rq;
if (on_rq)
- deactivate_task(rq, p, 0);
+ dequeue_task(rq, p, 0);
__setscheduler(rq, p, SCHED_NORMAL, 0);
if (on_rq) {
- activate_task(rq, p, 0);
+ enqueue_task(rq, p, 0);
resched_task(rq->curr);
}
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 84adb2d66cbd..7c6414fc669d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4866,6 +4866,15 @@ static void nohz_balancer_kick(int cpu)
return;
}
+static inline void clear_nohz_tick_stopped(int cpu)
+{
+ if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) {
+ cpumask_clear_cpu(cpu, nohz.idle_cpus_mask);
+ atomic_dec(&nohz.nr_cpus);
+ clear_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
+ }
+}
+
static inline void set_cpu_sd_state_busy(void)
{
struct sched_domain *sd;
@@ -4904,6 +4913,12 @@ void select_nohz_load_balancer(int stop_tick)
{
int cpu = smp_processor_id();
+ /*
+ * If this cpu is going down, then nothing needs to be done.
+ */
+ if (!cpu_active(cpu))
+ return;
+
if (stop_tick) {
if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))
return;
@@ -4914,6 +4929,18 @@ void select_nohz_load_balancer(int stop_tick)
}
return;
}
+
+static int __cpuinit sched_ilb_notifier(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_DYING:
+ clear_nohz_tick_stopped(smp_processor_id());
+ return NOTIFY_OK;
+ default:
+ return NOTIFY_DONE;
+ }
+}
#endif
static DEFINE_SPINLOCK(balancing);
@@ -5070,11 +5097,7 @@ static inline int nohz_kick_needed(struct rq *rq, int cpu)
* busy tick after returning from idle, we will update the busy stats.
*/
set_cpu_sd_state_busy();
- if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) {
- clear_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
- cpumask_clear_cpu(cpu, nohz.idle_cpus_mask);
- atomic_dec(&nohz.nr_cpus);
- }
+ clear_nohz_tick_stopped(cpu);
/*
* None are in tickless mode and hence no need for NOHZ idle load
@@ -5590,6 +5613,7 @@ __init void init_sched_fair_class(void)
#ifdef CONFIG_NO_HZ
zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
+ cpu_notifier(sched_ilb_notifier, 0);
#endif
#endif /* SMP */
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 3640ebbb466b..f42ae7fb5ec5 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1587,6 +1587,11 @@ static int push_rt_task(struct rq *rq)
if (!next_task)
return 0;
+#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
+ if (unlikely(task_running(rq, next_task)))
+ return 0;
+#endif
+
retry:
if (unlikely(next_task == rq->curr)) {
WARN_ON(1);
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 1d7bca7f4f52..d117262deba3 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -296,7 +296,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
if (__this_cpu_read(soft_watchdog_warn) == true)
return HRTIMER_RESTART;
- printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
+ printk(KERN_EMERG "BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
smp_processor_id(), duration,
current->comm, task_pid_nr(current));
print_modules();
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.