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Subject[PATCH rcu 05/25] rcutorture: Verify RCU reader prevents full polling from completing
Date
This commit adds a test to rcu_torture_writer() that verifies that a
->get_gp_state_full() and ->poll_gp_state_full() polled grace-period
sequence does not claim that a grace period elapsed within the confines
of the corresponding read-side critical section.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/rcutorture.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index f2564c7633a8a..050f4d0a987ff 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1309,6 +1309,8 @@ rcu_torture_writer(void *arg)
atomic_inc(&rcu_torture_wcount[i]);
WRITE_ONCE(old_rp->rtort_pipe_count,
old_rp->rtort_pipe_count + 1);
+
+ // Make sure readers block polled grace periods.
if (cur_ops->get_gp_state && cur_ops->poll_gp_state) {
idx = cur_ops->readlock();
cookie = cur_ops->get_gp_state();
@@ -1325,9 +1327,20 @@ rcu_torture_writer(void *arg)
}
cur_ops->readunlock(idx);
}
- if (cur_ops->get_gp_completed_full && cur_ops->poll_gp_state_full) {
- cur_ops->get_gp_completed_full(&cookie_full);
- WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full));
+ if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) {
+ idx = cur_ops->readlock();
+ cur_ops->get_gp_state_full(&cookie_full);
+ WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
+ "%s: Cookie check 5 failed %s(%d) online %*pbl\n",
+ __func__,
+ rcu_torture_writer_state_getname(),
+ rcu_torture_writer_state,
+ cpumask_pr_args(cpu_online_mask));
+ if (cur_ops->get_gp_completed_full) {
+ cur_ops->get_gp_completed_full(&cookie_full);
+ WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full));
+ }
+ cur_ops->readunlock(idx);
}
switch (synctype[torture_random(&rand) % nsynctypes]) {
case RTWS_DEF_FREE:
--
2.31.1.189.g2e36527f23
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