Commit 521c89b3 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Print human-readable message for schedule() in RCU reader 



The WARN_ON_ONCE() invocation within the CONFIG_PREEMPT=y version of
rcu_note_context_switch() triggers when there is a voluntary context
switch in an RCU read-side critical section, but there is quite a gap
between the output of that WARN_ON_ONCE() and this RCU-usage error.
This commit therefore converts the WARN_ON_ONCE() to a WARN_ONCE()
that explicitly describes the problem in its message.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 50895825

kernel/rcu/tree_plugin.h

+1 −1
Original line number Diff line number Diff line
@@ -346,7 +346,7 @@ void rcu_note_context_switch(bool preempt) 


	trace_rcu_utilization(TPS("Start context switch"));

	lockdep_assert_irqs_disabled();

	WARN_ON_ONCE(!preempt && rcu_preempt_depth() > 0);

	WARN_ONCE(!preempt && rcu_preempt_depth() > 0, "Voluntary context switch within RCU read-side critical section!");

	if (rcu_preempt_depth() > 0 &&

	    !t->rcu_read_unlock_special.b.blocked) {