[008/156] timekeeping: Prevent oops when GENERIC_TIME=n

[Greg KH]

2.6.33-stable review patch.  If anyone has any objections, please let us know.

------------------

From: john stultz <johnstul@xxxxxxxxxx>

commit ad6759fbf35d104dbf573cd6f4c6784ad6823f7e upstream.

Aaro Koskinen reported an issue in kernel.org bugzilla #15366, where
on non-GENERIC_TIME systems, accessing
/sys/devices/system/clocksource/clocksource0/current_clocksource
results in an oops.

It seems the timekeeper/clocksource rework missed initializing the
curr_clocksource value in the !GENERIC_TIME case.

Thanks to Aaro for reporting and diagnosing the issue as well as
testing the fix!

Reported-by: Aaro Koskinen <aaro.koskinen@xxxxxx>
Signed-off-by: John Stultz <johnstul@xxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
LKML-Reference: <1267475683.4216.61.camel@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 kernel/time/clocksource.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -580,6 +580,10 @@ static inline void clocksource_select(vo
  */
 static int __init clocksource_done_booting(void)
 {
+	mutex_lock(&clocksource_mutex);
+	curr_clocksource = clocksource_default_clock();
+	mutex_unlock(&clocksource_mutex);
+
 	finished_booting = 1;
 
 	/*


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