From: Yong Zhang Date: Mon, 11 Jan 2010 06:21:25 +0000 (+0800) Subject: sched: Reassign prev and switch_count when reacquire_kernel_lock() fail X-Git-Tag: v2.6.33-rc5~2^2 X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=6d558c3ac9b6508d26fd5cadccce51fc9d726b1c sched: Reassign prev and switch_count when reacquire_kernel_lock() fail Assume A->B schedule is processing, if B have acquired BKL before and it need reschedule this time. Then on B's context, it will go to need_resched_nonpreemptible for reschedule. But at this time, prev and switch_count are related to A. It's wrong and will lead to incorrect scheduler statistics. Signed-off-by: Yong Zhang Signed-off-by: Peter Zijlstra LKML-Reference: <2674af741001102238w7b0ddcadref00d345e2181d11@mail.gmail.com> Signed-off-by: Ingo Molnar --- diff --git a/kernel/sched.c b/kernel/sched.c index c535cc4..4508fe7 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5530,8 +5530,11 @@ need_resched_nonpreemptible: post_schedule(rq); - if (unlikely(reacquire_kernel_lock(current) < 0)) + if (unlikely(reacquire_kernel_lock(current) < 0)) { + prev = rq->curr; + switch_count = &prev->nivcsw; goto need_resched_nonpreemptible; + } preempt_enable_no_resched(); if (need_resched())