hrtimer: prevent migration of per CPU hrtimers
Impact: per CPU hrtimers can be migrated from a dead CPU
The hrtimer code has no knowledge about per CPU timers, but we need to
prevent the migration of such timers and warn when such a timer is
active at migration time.
Explicitely mark the timers as per CPU and use a more understandable
mode descriptor for the interrupts safe unlocked callback mode, which
is used by hrtimer_sleeper and the scheduler code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index bdd88df..2f245fe 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -47,14 +47,22 @@
* HRTIMER_CB_IRQSAFE: Callback may run in hardirq context
* HRTIMER_CB_IRQSAFE_NO_RESTART: Callback may run in hardirq context and
* does not restart the timer
- * HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: Callback must run in hardirq context
- * Special mode for tick emultation
+ * HRTIMER_CB_IRQSAFE_PERCPU: Callback must run in hardirq context
+ * Special mode for tick emulation and
+ * scheduler timer. Such timers are per
+ * cpu and not allowed to be migrated on
+ * cpu unplug.
+ * HRTIMER_CB_IRQSAFE_UNLOCKED: Callback should run in hardirq context
+ * with timer->base lock unlocked
+ * used for timers which call wakeup to
+ * avoid lock order problems with rq->lock
*/
enum hrtimer_cb_mode {
HRTIMER_CB_SOFTIRQ,
HRTIMER_CB_IRQSAFE,
HRTIMER_CB_IRQSAFE_NO_RESTART,
- HRTIMER_CB_IRQSAFE_NO_SOFTIRQ,
+ HRTIMER_CB_IRQSAFE_PERCPU,
+ HRTIMER_CB_IRQSAFE_UNLOCKED,
};
/*