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-rw-r--r--include/linux/hrtimer.h4
-rw-r--r--kernel/hrtimer.c12
2 files changed, 13 insertions, 3 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 6d93dce..bdd88df 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -67,9 +67,10 @@ enum hrtimer_cb_mode {
* 0x02 callback function running
* 0x04 callback pending (high resolution mode)
*
- * Special case:
+ * Special cases:
* 0x03 callback function running and enqueued
* (was requeued on another CPU)
+ * 0x09 timer was migrated on CPU hotunplug
* The "callback function running and enqueued" status is only possible on
* SMP. It happens for example when a posix timer expired and the callback
* queued a signal. Between dropping the lock which protects the posix timer
@@ -87,6 +88,7 @@ enum hrtimer_cb_mode {
#define HRTIMER_STATE_ENQUEUED 0x01
#define HRTIMER_STATE_CALLBACK 0x02
#define HRTIMER_STATE_PENDING 0x04
+#define HRTIMER_STATE_MIGRATE 0x08
/**
* struct hrtimer - the basic hrtimer structure
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index ac2f6d6..ace723d 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1602,7 +1602,13 @@ static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
timer = rb_entry(node, struct hrtimer, node);
BUG_ON(hrtimer_callback_running(timer));
debug_hrtimer_deactivate(timer);
- __remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE, 0);
+
+ /*
+ * Mark it as STATE_MIGRATE not INACTIVE otherwise the
+ * timer could be seen as !active and just vanish away
+ * under us on another CPU
+ */
+ __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
timer->base = new_base;
/*
* Enqueue the timer. Allow reprogramming of the event device
@@ -1620,13 +1626,15 @@ static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
* state, we need to do that otherwise we end up with
* a stale timer.
*/
- if (timer->state == HRTIMER_STATE_INACTIVE) {
+ if (timer->state == HRTIMER_STATE_MIGRATE) {
timer->state = HRTIMER_STATE_PENDING;
list_add_tail(&timer->cb_entry,
&new_base->cpu_base->cb_pending);
raise = 1;
}
#endif
+ /* Clear the migration state bit */
+ timer->state &= ~HRTIMER_STATE_MIGRATE;
}
return raise;
}
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