[PATCH] rcutorture: Call preempt_schedule() through static call/key

[Frederic Weisbecker]

rcutorture sometimes want to trigger a random scheduler preemption call
while simulating a read delay. However a direct call to
preempt_schedule() is not desirable because it bypasses the static
call/key filter used by CONFIG_PREEMPT_DYNAMIC. This breaks the
no-preempt assumption in case the dynamic preemption mode is "none".

For example rcu_blocking_is_gp() is fooled and abbreviates grace periods
when the CPU runs in no-preempt UP mode.

Fix this with making torture_preempt_schedule() to call through
preempt dynamic static call/key.

Reported-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
---
 include/linux/torture.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/torture.h b/include/linux/torture.h
index 63fa4196e51c..7038104463e4 100644
--- a/include/linux/torture.h
+++ b/include/linux/torture.h
@@ -118,7 +118,7 @@ void _torture_stop_kthread(char *m, struct task_struct **tp);
 	_torture_stop_kthread("Stopping " #n " task", &(tp))
 
 #ifdef CONFIG_PREEMPTION
-#define torture_preempt_schedule() preempt_schedule()
+#define torture_preempt_schedule() __preempt_schedule()
 #else
 #define torture_preempt_schedule()	do { } while (0)
 #endif
-- 
2.25.1