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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-04-27 16:13:53 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-06-08 08:25:34 -0700
commitf4687d2637a4016b2eedfdb777105c95e8d6fe52 (patch)
tree1a6f94344dc126fd0e48287990f6486581734454 /kernel/rcu
parentc75e9caaf85f1fc4ed32e510b259d67ec3c4c603 (diff)
downloadlinux-f4687d2637a4016b2eedfdb777105c95e8d6fe52.tar.gz
rcu: Add preemptibility checks in rcu_sched_qs() and rcu_bh_qs()
This commit adds WARN_ON_ONCE() calls that trigger if either
rcu_sched_qs() or rcu_bh_qs() are invoked with preemption enabled.
In the immortal words of Peter Zijlstra: "these are much harder to ignore
than comments".

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 3bee58fc23b1..b01a02e7a0b7 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -250,6 +250,7 @@ static int rcu_gp_in_progress(struct rcu_state *rsp)
  */
 void rcu_sched_qs(void)
 {
+	RCU_LOCKDEP_WARN(preemptible(), "rcu_sched_qs() invoked with preemption enabled!!!");
 	if (!__this_cpu_read(rcu_sched_data.cpu_no_qs.s))
 		return;
 	trace_rcu_grace_period(TPS("rcu_sched"),
@@ -265,6 +266,7 @@ void rcu_sched_qs(void)
 
 void rcu_bh_qs(void)
 {
+	RCU_LOCKDEP_WARN(preemptible(), "rcu_bh_qs() invoked with preemption enabled!!!");
 	if (__this_cpu_read(rcu_bh_data.cpu_no_qs.s)) {
 		trace_rcu_grace_period(TPS("rcu_bh"),
 				       __this_cpu_read(rcu_bh_data.gpnum),