@@ -1269,7 +1269,12 @@ rcu_torture_writer(void *arg)
break;
case RTWS_EXP_SYNC:
rcu_torture_writer_state = RTWS_EXP_SYNC;
+ if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
+ cookie = cur_ops->get_gp_state();
cur_ops->exp_sync();
+ cur_ops->exp_sync();
+ if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
+ WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie));
rcu_torture_pipe_update(old_rp);
break;
case RTWS_COND_GET:
@@ -1291,7 +1296,12 @@ rcu_torture_writer(void *arg)
break;
case RTWS_SYNC:
rcu_torture_writer_state = RTWS_SYNC;
+ if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
+ cookie = cur_ops->get_gp_state();
cur_ops->sync();
+ cur_ops->sync();
+ if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
+ WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie));
rcu_torture_pipe_update(old_rp);
break;
default:
This commit causes rcu_torture_writer() to use WARN_ON_ONCE() to check that the cookie returned by the current RCU flavor's ->get_gp_state() function (get_state_synchronize_rcu() for vanilla RCU) causes that flavor's ->poll_gp_state function (poll_state_synchronize_rcu() for vanilla RCU) to unconditionally return true. Note that a pair calls to synchronous grace-period-wait functions are used. This is necessary to account for partially overlapping normal and expedited grace periods aligning in just the wrong way with polled API invocations, which can cause those polled API invocations to ignore one or the other of those partially overlapping grace periods. It is unlikely that this sort of ignored grace period will be a problem in production, but rcutorture can make it happen quite within a few tens of seconds. This commit is in preparation for polled expedited grace periods. [ paulmck: Apply feedback from Frederic Weisbecker. ] Link: https://lore.kernel.org/all/20220121142454.1994916-1-bfoster@redhat.com/ Link: https://docs.google.com/document/d/1RNKWW9jQyfjxw2E8dsXVTdvZYh0HnYeSHDKog9jhdN8/edit?usp=sharing Cc: Brian Foster <bfoster@redhat.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ian Kent <raven@themaw.net> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> --- kernel/rcu/rcutorture.c | 10 ++++++++++ 1 file changed, 10 insertions(+)