The latency tracer can call clocksource_read very early in bootup and before the clock source variable has been initialized. This results in a crash at boot up (even before earlyprintk is initialized). Since the clock->read variable is points to NULL. This patch simply initializes the clock to use clocksource_jiffies, so that any early user of clocksource_read will not crash. Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Index: linux-2.6-rt/kernel/time/timekeeping.c =================================================================== --- linux-2.6-rt.orig/kernel/time/timekeeping.c 2007-08-24 11:38:11.000000000 -0400 +++ linux-2.6-rt/kernel/time/timekeeping.c 2007-08-24 13:41:03.000000000 -0400 @@ -43,7 +43,15 @@ struct timespec wall_to_monotonic __attr EXPORT_SYMBOL(xtime); -static struct clocksource *clock; /* pointer to current clocksource */ +extern struct clocksource clocksource_jiffies; + +/* + * pointer to current clocksource + * Just in case we use clocksource_read before we initialize + * the actual clock source. Instead of calling a NULL read pointer + * we return jiffies. + */ +static struct clocksource *clock = &clocksource_jiffies; #ifdef CONFIG_GENERIC_TIME - To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
