Commit-ID: c74859d1eb2d8578bdf6d78ba893e394085aba1a
Gitweb: https://git.kernel.org/tip/c74859d1eb2d8578bdf6d78ba893e394085aba1a
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Fri, 27 Apr 2018 14:05:27 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Thu, 12 Jul 2018 15:38:59 -0700
rcu: Make rcu_report_unblock_qs_rnp() warn on violated preconditions
If rcu_report_unblock_qs_rnp() is invoked on something other than
preemptible RCU or if there are still preempted tasks blocking the
current grace period, something went badly wrong in the caller.
This commit therefore adds WARN_ON_ONCE() to these conditions, but
leaving the legitimate reason for early exit (rnp->qsmask != 0)
unwarned.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 3fe854a15d82..85417584ffd0 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2308,8 +2308,10 @@ static void rcu_report_unblock_qs_rnp(struct rcu_state *rsp,
struct rcu_node *rnp_p;
raw_lockdep_assert_held_rcu_node(rnp);
- if (rcu_state_p == &rcu_sched_state || rsp != rcu_state_p ||
- rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) {
+ if (WARN_ON_ONCE(rcu_state_p == &rcu_sched_state) ||
+ WARN_ON_ONCE(rsp != rcu_state_p) ||
+ WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)) ||
+ rnp->qsmask != 0) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return; /* Still need more quiescent states! */
}
--
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