[PATCH 4.2 51/54] timekeeping: Increment clock_was_set_seq in timekeeping_init()

Greg Kroah-Hartman
2015-10-23T18:28:30Z

From: Thomas Gleixner <tglx@linutronix.de>

commit 56fd16cabac9cd8f15e2902898a9d0cc96e2fa70 upstream.

timekeeping_init() can set the wall time offset, so we need to
increment the clock_was_set_seq counter. That way hrtimers will pick
up the early offset immediately. Otherwise on a machine which does not
set wall time later in the boot process the hrtimer offset is stale at
0 and wall time timers are going to expire with a delay of 45 years.

Fixes: 868a3e915f7f "hrtimer: Make offset update smarter"
Reported-and-tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Stefan Liebler <stli@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/time/timekeeping.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1244,7 +1244,7 @@ void __init timekeeping_init(void)
set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
tk_set_wall_to_mono(tk, tmp);

- timekeeping_update(tk, TK_MIRROR);
+ timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);

write_seqcount_end(&tk_core.seq);
raw_spin_unlock_irqrestore(&timekeeper_lock, flags);