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 <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> LKML-Reference: <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
rtvt123 · Jan 21, 2010 · 6d558c3 · 6d558c3
1 parent 50b926e
commit 6d558c3
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/kernel/sched.c b/kernel/sched.c
@@ -5530,8 +5530,11 @@ asmlinkage void __sched schedule(void)
 
 	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())