From 775227511843202e65a7f194cbf64f38de01f004 Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@kernel.org>
Date: Thu, 11 Jun 2020 16:43:14 -0700
Subject: [PATCH] rcutorture: Check for unwatched readers

RCU is supposed to be watching all non-idle kernel code and also all
softirq handlers.  This commit adds some teeth to this statement by
adding a WARN_ON_ONCE().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/rcutorture.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 37455a12898e6..9c310016585b7 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1377,6 +1377,7 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp)
 	struct rt_read_seg *rtrsp1;
 	unsigned long long ts;
 
+	WARN_ON_ONCE(!rcu_is_watching());
 	newstate = rcutorture_extend_mask(readstate, trsp);
 	rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
 	started = cur_ops->get_gp_seq();