commit 995f054f2a342f8505fed4f8395d12c0f5966414
author Ingo Molnar <mingo@elte.hu> Sat Apr 07 12:05:00 2007 +0200
committer Linus Torvalds <torvalds@woody.linux-foundation.org> Sat Apr 07 10:03:43 2007 -0700
tree 08ddf96e3365d2b0a9940914fdb179810fbca3a0
parent bbef618190fb484b28b7d441e6fc5d524027c4fa

[PATCH] high-res timers: resume fix

Soeren Sonnenburg reported that upon resume he is getting
this backtrace:

 [<c0119637>] smp_apic_timer_interrupt+0x57/0x90
 [<c0142d30>] retrigger_next_event+0x0/0xb0
 [<c0104d30>] apic_timer_interrupt+0x28/0x30
 [<c0142d30>] retrigger_next_event+0x0/0xb0
 [<c0140068>] __kfifo_put+0x8/0x90
 [<c0130fe5>] on_each_cpu+0x35/0x60
 [<c0143538>] clock_was_set+0x18/0x20
 [<c0135cdc>] timekeeping_resume+0x7c/0xa0
 [<c02aabe1>] __sysdev_resume+0x11/0x80
 [<c02ab0c7>] sysdev_resume+0x47/0x80
 [<c02b0b05>] device_power_up+0x5/0x10

it turns out that on resume we mistakenly re-enable interrupts too
early.  Do the timer retrigger only on the current CPU.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Soeren Sonnenburg <kernel@nn7.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/hrtimer.h

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 5bdbc74..17c29dc 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -206,6 +206,7 @@
 struct clock_event_device;
 
 extern void clock_was_set(void);
+extern void hres_timers_resume(void);
 extern void hrtimer_interrupt(struct clock_event_device *dev);
 
 /*
@@ -236,6 +237,8 @@
  */
 static inline void clock_was_set(void) { }
 
+static inline void hres_timers_resume(void) { }
+
 /*
  * In non high resolution mode the time reference is taken from
  * the base softirq time variable.

kernel/hrtimer.c

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 067ba2c..b74860a 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -459,6 +459,18 @@
 }
 
 /*
+ * During resume we might have to reprogram the high resolution timer
+ * interrupt (on the local CPU):
+ */
+void hres_timers_resume(void)
+{
+	WARN_ON_ONCE(num_online_cpus() > 1);
+
+	/* Retrigger the CPU local events: */
+	retrigger_next_event(NULL);
+}
+
+/*
  * Check, whether the timer is on the callback pending list
  */
 static inline int hrtimer_cb_pending(const struct hrtimer *timer)

kernel/timer.c

diff --git a/kernel/timer.c b/kernel/timer.c
index 440048a..dd6c2c1 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1016,7 +1016,7 @@
 	clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);
 
 	/* Resume hrtimers */
-	clock_was_set();
+	hres_timers_resume();
 
 	return 0;
 }