[PATCH] clockevents: Fix suspend/resume to disk hangs

I finally found a dual core box, which survives suspend/resume without
crashing in the middle of nowhere. Sigh, I never figured out from the
code and the bug reports what's going on.

The observed hangs are caused by a stale state transition of the clock
event devices, which keeps the RCU synchronization away from completion,
when the non boot CPU is brought back up.

The suspend/resume in oneshot mode needs the similar care as the
periodic mode during suspend to RAM. My assumption that the state
transitions during the different shutdown/bringups of s2disk would go
through the periodic boot phase and then switch over to highres resp.
nohz mode were simply wrong.

Add the appropriate suspend / resume handling for the non periodic
modes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 1 deletions

diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 75890efd24ff..c9d203bde518 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -19,12 +19,13 @@ extern void tick_setup_oneshot(struct clock_event_device *newdev,
 extern int tick_program_event(ktime_t expires, int force);
 extern void tick_oneshot_notify(void);
 extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *));
-
+extern void tick_resume_oneshot(void);
 # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 extern void tick_broadcast_setup_oneshot(struct clock_event_device *bc);
 extern void tick_broadcast_oneshot_control(unsigned long reason);
 extern void tick_broadcast_switch_to_oneshot(void);
 extern void tick_shutdown_broadcast_oneshot(unsigned int *cpup);
+extern int tick_resume_broadcast_oneshot(struct clock_event_device *bc);
 # else /* BROADCAST */
 static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 {
@@ -43,6 +44,10 @@ void tick_setup_oneshot(struct clock_event_device *newdev,
 {
         BUG();
 }
+static inline void tick_resume_oneshot(void)
+{
+        BUG();
+}
 static inline int tick_program_event(ktime_t expires, int force)
 {
         return 0;
@@ -54,6 +59,10 @@ static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 }
 static inline void tick_broadcast_oneshot_control(unsigned long reason) { }
 static inline void tick_shutdown_broadcast_oneshot(unsigned int *cpup) { }
+static inline int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
+{
+        return 0;
+}
 #endif /* !TICK_ONESHOT */
 
 /*