From 6409c4da289d6905f7ae2bd0630438368439bda2 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 12 May 2008 21:21:14 +0200 Subject: [PATCH] sched: sched_clock() improvement: use in_nmi() make sure we dont execute more complex sched_clock() code in NMI context. Acked-by: Peter Zijlstra Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/sched_clock.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index a0b0852414cc..db69174b1178 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -29,6 +29,7 @@ #include #include #include +#include /* * Scheduler clock - returns current time in nanosec units. @@ -151,6 +152,13 @@ u64 sched_clock_cpu(int cpu) struct sched_clock_data *scd = cpu_sdc(cpu); u64 now, clock, this_clock, remote_clock; + /* + * Normally this is not called in NMI context - but if it is, + * trying to do any locking here is totally lethal. + */ + if (unlikely(in_nmi())) + return scd->clock; + if (unlikely(!sched_clock_running)) return 0ull; -- 2.39.5