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authorLinus Torvalds <torvalds@linux-foundation.org>2015-03-28 11:21:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-03-28 11:21:23 -0700
commit4a89452e70a019cb6bfb1114b12f2607c3bace24 (patch)
tree4744009041b3fb9d2b78621d2f6ab42c01b1cb3a /kernel
parent19dba4f3e9f7fef811cf446e15f578887762528a (diff)
parent6e206020324c50a95486f6b279a53512febed92d (diff)
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Ingo Molnar: "Two clocksource driver fixes, and an idle loop RCU warning fix" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource/drivers/sun5i: Fix cpufreq interaction with sched_clock() clocksource/drivers: Fix various !CONFIG_HAS_IOMEM build errors timers/tick/broadcast-hrtimer: Fix suspicious RCU usage in idle loop
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time/tick-broadcast-hrtimer.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/time/tick-broadcast-hrtimer.c b/kernel/time/tick-broadcast-hrtimer.c
index eb682d5c697c..6aac4beedbbe 100644
--- a/kernel/time/tick-broadcast-hrtimer.c
+++ b/kernel/time/tick-broadcast-hrtimer.c
@@ -49,6 +49,7 @@ static void bc_set_mode(enum clock_event_mode mode,
*/
static int bc_set_next(ktime_t expires, struct clock_event_device *bc)
{
+ int bc_moved;
/*
* We try to cancel the timer first. If the callback is on
* flight on some other cpu then we let it handle it. If we
@@ -60,9 +61,15 @@ static int bc_set_next(ktime_t expires, struct clock_event_device *bc)
* restart the timer because we are in the callback, but we
* can set the expiry time and let the callback return
* HRTIMER_RESTART.
+ *
+ * Since we are in the idle loop at this point and because
+ * hrtimer_{start/cancel} functions call into tracing,
+ * calls to these functions must be bound within RCU_NONIDLE.
*/
- if (hrtimer_try_to_cancel(&bctimer) >= 0) {
- hrtimer_start(&bctimer, expires, HRTIMER_MODE_ABS_PINNED);
+ RCU_NONIDLE(bc_moved = (hrtimer_try_to_cancel(&bctimer) >= 0) ?
+ !hrtimer_start(&bctimer, expires, HRTIMER_MODE_ABS_PINNED) :
+ 0);
+ if (bc_moved) {
/* Bind the "device" to the cpu */
bc->bound_on = smp_processor_id();
} else if (bc->bound_on == smp_processor_id()) {