diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2017-08-31 18:19:06 +0200 |
|---|---|---|
| committer | Luis Claudio R. Goncalves <lgoncalv@redhat.com> | 2021-10-11 07:51:27 -0300 |
| commit | 8af264204a92b1bc764a2f5476073b4cdd1a616d (patch) | |
| tree | ebd15931c2fba8f057af35555bfdd6eb3190e0ae /kernel/time | |
| parent | 8dba09568c1b48ddd950d8f065215a47b355f99f (diff) | |
| download | linux-rt-8af264204a92b1bc764a2f5476073b4cdd1a616d.tar.gz | |
kernel/hrtimer: don't wakeup a process while holding the hrtimer base lock
We must not wake any process (and thus acquire the pi->lock) while
holding the hrtimer's base lock. This does not happen usually because
the hrtimer-callback is invoked in IRQ-context and so
raise_softirq_irqoff() does not wakeup a process.
However during CPU-hotplug it might get called from hrtimers_dead_cpu()
which would wakeup the thread immediately.
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/hrtimer.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index a641e549d12c..b53cb2405417 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1450,7 +1450,7 @@ static inline int hrtimer_rt_defer(struct hrtimer *timer) { return 0; } static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer); -static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now) +static int __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now) { struct hrtimer_clock_base *base = cpu_base->clock_base; unsigned int active = cpu_base->active_bases; @@ -1500,8 +1500,7 @@ static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now) raise = 1; } } - if (raise) - raise_softirq_irqoff(HRTIMER_SOFTIRQ); + return raise; } #ifdef CONFIG_HIGH_RES_TIMERS @@ -1515,6 +1514,7 @@ void hrtimer_interrupt(struct clock_event_device *dev) struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases); ktime_t expires_next, now, entry_time, delta; int retries = 0; + int raise; BUG_ON(!cpu_base->hres_active); cpu_base->nr_events++; @@ -1533,7 +1533,7 @@ retry: */ cpu_base->expires_next.tv64 = KTIME_MAX; - __hrtimer_run_queues(cpu_base, now); + raise = __hrtimer_run_queues(cpu_base, now); /* Reevaluate the clock bases for the next expiry */ expires_next = __hrtimer_get_next_event(cpu_base); @@ -1544,6 +1544,8 @@ retry: cpu_base->expires_next = expires_next; cpu_base->in_hrtirq = 0; raw_spin_unlock(&cpu_base->lock); + if (raise) + raise_softirq_irqoff(HRTIMER_SOFTIRQ); /* Reprogramming necessary ? */ if (!tick_program_event(expires_next, 0)) { @@ -1623,6 +1625,7 @@ void hrtimer_run_queues(void) { struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases); ktime_t now; + int raise; if (__hrtimer_hres_active(cpu_base)) return; @@ -1641,8 +1644,10 @@ void hrtimer_run_queues(void) raw_spin_lock(&cpu_base->lock); now = hrtimer_update_base(cpu_base); - __hrtimer_run_queues(cpu_base, now); + raise = __hrtimer_run_queues(cpu_base, now); raw_spin_unlock(&cpu_base->lock); + if (raise) + raise_softirq_irqoff(HRTIMER_SOFTIRQ); } /* |