rcutorture: Verify long-running reader prevents full polling from completing

This commit adds full-state polling checks to accompany the old-style
polling checks in the rcu_torture_one_read() function.  If a polling
cycle within an RCU reader completes, a WARN_ONCE() is triggered.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 236bd6b57277f2dfef13c1d89a634fd3121acff1..3d85420108477f5dd4335e8a3f00703b5448c6ab 100644 (file)
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1770,6 +1770,7 @@ rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
 {
        unsigned long cookie;
+       struct rcu_gp_oldstate cookie_full;
        int i;
        unsigned long started;
        unsigned long completed;
@@ -1787,6 +1788,8 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
        rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
        if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
                cookie = cur_ops->get_gp_state();
+       if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
+               cur_ops->get_gp_state_full(&cookie_full);
        started = cur_ops->get_gp_seq();
        ts = rcu_trace_clock_local();
        p = rcu_dereference_check(rcu_torture_current,
@@ -1827,6 +1830,13 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
                          rcu_torture_writer_state_getname(),
                          rcu_torture_writer_state,
                          cookie, cur_ops->get_gp_state());
+       if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
+               WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
+                         "%s: Cookie check 6 failed %s(%d) online %*pbl\n",
+                         __func__,
+                         rcu_torture_writer_state_getname(),
+                         rcu_torture_writer_state,
+                         cpumask_pr_args(cpu_online_mask));
        rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
        WARN_ON_ONCE(readstate);
        // This next splat is expected behavior if leakpointer, especially