92 lines
3.0 KiB
Diff
92 lines
3.0 KiB
Diff
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From aaa8caa9aa399fc8d31be22068755cc519f2d5bf Mon Sep 17 00:00:00 2001
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Thu, 31 Aug 2017 18:19:06 +0200
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Subject: [PATCH 336/365] kernel/hrtimer: don't wakeup a process while holding
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the hrtimer base lock
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We must not wake any process (and thus acquire the pi->lock) while
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holding the hrtimer's base lock. This does not happen usually because
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the hrtimer-callback is invoked in IRQ-context and so
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raise_softirq_irqoff() does not wakeup a process.
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However during CPU-hotplug it might get called from hrtimers_dead_cpu()
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which would wakeup the thread immediately.
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Reported-by: Mike Galbraith <efault@gmx.de>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/time/hrtimer.c | 15 ++++++++++-----
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1 file changed, 10 insertions(+), 5 deletions(-)
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diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
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index 0860d60957cd..bfe46fe6a700 100644
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--- a/kernel/time/hrtimer.c
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+++ b/kernel/time/hrtimer.c
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@@ -1450,7 +1450,7 @@ static inline int hrtimer_rt_defer(struct hrtimer *timer) { return 0; }
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static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer);
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-static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now)
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+static int __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now)
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{
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struct hrtimer_clock_base *base = cpu_base->clock_base;
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unsigned int active = cpu_base->active_bases;
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@@ -1500,8 +1500,7 @@ static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now)
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raise = 1;
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}
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}
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- if (raise)
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- raise_softirq_irqoff(HRTIMER_SOFTIRQ);
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+ return raise;
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}
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#ifdef CONFIG_HIGH_RES_TIMERS
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@@ -1515,6 +1514,7 @@ void hrtimer_interrupt(struct clock_event_device *dev)
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struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
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ktime_t expires_next, now, entry_time, delta;
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int retries = 0;
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+ int raise;
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BUG_ON(!cpu_base->hres_active);
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cpu_base->nr_events++;
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@@ -1533,7 +1533,7 @@ void hrtimer_interrupt(struct clock_event_device *dev)
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*/
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cpu_base->expires_next.tv64 = KTIME_MAX;
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- __hrtimer_run_queues(cpu_base, now);
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+ raise = __hrtimer_run_queues(cpu_base, now);
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/* Reevaluate the clock bases for the next expiry */
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expires_next = __hrtimer_get_next_event(cpu_base);
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@@ -1544,6 +1544,8 @@ void hrtimer_interrupt(struct clock_event_device *dev)
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cpu_base->expires_next = expires_next;
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cpu_base->in_hrtirq = 0;
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raw_spin_unlock(&cpu_base->lock);
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+ if (raise)
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+ raise_softirq_irqoff(HRTIMER_SOFTIRQ);
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/* Reprogramming necessary ? */
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if (!tick_program_event(expires_next, 0)) {
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@@ -1623,6 +1625,7 @@ void hrtimer_run_queues(void)
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{
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struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
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ktime_t now;
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+ int raise;
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if (__hrtimer_hres_active(cpu_base))
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return;
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@@ -1641,8 +1644,10 @@ void hrtimer_run_queues(void)
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raw_spin_lock(&cpu_base->lock);
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now = hrtimer_update_base(cpu_base);
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- __hrtimer_run_queues(cpu_base, now);
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+ raise = __hrtimer_run_queues(cpu_base, now);
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raw_spin_unlock(&cpu_base->lock);
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+ if (raise)
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+ raise_softirq_irqoff(HRTIMER_SOFTIRQ);
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}
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/*
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--
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2.28.0
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