[tip: core/rcu] refscale: Prevent hangs for invalid arguments

[tip-bot2 for Paul E. McKenney]

The following commit has been merged into the core/rcu branch of tip:

Commit-ID:     bc80d353b3f565138cda7e95ed4020e6e69360b2
Gitweb:        https://git.kernel.org/tip/bc80d353b3f565138cda7e95ed4020e6e69360b2
Author:        Paul E. McKenney <paulmck@xxxxxxxxxx>
AuthorDate:    Thu, 17 Sep 2020 10:37:10 -07:00
Committer:     Paul E. McKenney <paulmck@xxxxxxxxxx>
CommitterDate: Fri, 06 Nov 2020 17:13:51 -08:00

refscale: Prevent hangs for invalid arguments

If an refscale torture-test run is given a bad kvm.sh argument, the
test will complain to the console, which is good.  What is bad is that
from the user's perspective, it will just hang for the time specified
by the --duration argument.  This commit therefore forces an immediate
kernel shutdown if a ref_scale_init()-time error occurs, thus avoiding
the appearance of a hang.  It also forces a console splat in this case
to clearly indicate the presence of an error.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
 kernel/rcu/refscale.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index fb5f20d..23ff36a 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -658,7 +658,6 @@ ref_scale_init(void)
 		for (i = 0; i < ARRAY_SIZE(scale_ops); i++)
 			pr_cont(" %s", scale_ops[i]->name);
 		pr_cont("\n");
-		WARN_ON(!IS_MODULE(CONFIG_RCU_REF_SCALE_TEST));
 		firsterr = -EINVAL;
 		cur_ops = NULL;
 		goto unwind;
@@ -718,6 +717,10 @@ ref_scale_init(void)
 unwind:
 	torture_init_end();
 	ref_scale_cleanup();
+	if (shutdown) {
+		WARN_ON(!IS_MODULE(CONFIG_RCU_REF_SCALE_TEST));
+		kernel_power_off();
+	}
 	return firsterr;
 }