rcutorture: Fix cleanup path for invalid torture_type strings

BugLink: https://bugs.launchpad.net/bugs/1837517
[ Upstream commit b813afae7ab6a5e91b4e16cc567331d9c2ae1f04 ]

If the specified rcutorture.torture_type is not in the rcu_torture_init()
function's torture_ops[] array, rcutorture prints some console messages
and then invokes rcu_torture_cleanup() to set state so that a future
torture test can run.  However, rcu_torture_cleanup() also attempts to
end the test that didn't actually start, and in doing so relies on the
value of cur_ops, a value that is not particularly relevant in this case.
This can result in confusing output or even follow-on failures due to
attempts to use facilities that have not been properly initialized.

This commit therefore sets the value of cur_ops to NULL in this case
and inserts a check near the beginning of rcu_torture_cleanup(),
thus avoiding relying on an irrelevant cur_ops value.

Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index f6e85faa4ff4b33cb7c8170d029d470ca9f1065a..584b0d1da0a3b1f2bc97b5e0220ae96757c95e55 100644 (file)
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -2092,6 +2092,10 @@ rcu_torture_cleanup(void)
                        cur_ops->cb_barrier();
                return;
        }
+       if (!cur_ops) {
+               torture_cleanup_end();
+               return;
+       }
 
        rcu_torture_barrier_cleanup();
        torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task);
@@ -2257,6 +2261,7 @@ rcu_torture_init(void)
                pr_cont("\n");
                WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
                firsterr = -EINVAL;
+               cur_ops = NULL;
                goto unwind;
        }
        if (cur_ops->fqs == NULL && fqs_duration != 0) {