[RESEND][PATCH] Fix oops on !GENERIC_TIME systems when accessingcurrent_clocksource

From: john stultz
Date: Mon Mar 01 2010 - 15:35:04 EST

No one has replied to this, so I wanted to send it out again.

Aaro Koskinen reported an issue in bug #15366, where on non-GENERIC_TIME
accessing /sys/devices/system/clocksource/clocksource0/current_clocksource would oops the system.

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

The following patch makes sure it gets initialized, and avoids the

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

Bug Details: http://bugzilla.kernel.org/show_bug.cgi?id=15366

Too late for 2.6.33, but this likely should go into 2.6.33-stable and


Signed-off-by: John Stultz <johnstul@xxxxxxxxxx>

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index e85c234..c436ee5 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -568,6 +568,10 @@ static inline void clocksource_select(void) { }
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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