Commit 040ec23d authored Jun 09, 2008 by Ingo Molnar

sched: sched_clock() lockdep fix



Sitsofe Wheeler bisected the following commit to cause a lockdep to
warn about itself and turn itself off:

> commit c6531cce
> Author: Ingo Molnar <mingo@elte.hu>
> Date:   Mon May 12 21:21:14 2008 +0200
>
>     sched: do not trace sched_clock

do not use raw irq flags in cpu_clock() as it causes lockdep to lose
track of the true state of the IRQ flag.

Reported-and-bisected-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 34078a5e

kernel/sched.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -889,7 +889,7 @@ unsigned long long notrace cpu_clock(int cpu)
		unsigned long long prev_cpu_time, time, delta_time;
		unsigned long flags;

		raw_local_irq_save(flags);
		local_irq_save(flags);
		prev_cpu_time = per_cpu(prev_cpu_time, cpu);
		time = __cpu_clock(cpu) + per_cpu(time_offset, cpu);
		delta_time = time-prev_cpu_time;
		@@ -898,7 +898,7 @@ unsigned long long notrace cpu_clock(int cpu)
		time = __sync_cpu_clock(time, cpu);
		per_cpu(prev_cpu_time, cpu) = time;
		}
		raw_local_irq_restore(flags);
		local_irq_restore(flags);

		return time;
		}

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