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Commit f4687d26 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

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: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent c75e9caa

kernel/rcu/tree.c

+2 −0
Original line number Diff line number Diff line
@@ -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),