[tip: core/rcu] scftorture: Add cond_resched() to test loop

[tip-bot2 for Paul E. McKenney]

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

Commit-ID:     65bd77f554336407f5fd7ced7a6df686767fba21
Gitweb:        https://git.kernel.org/tip/65bd77f554336407f5fd7ced7a6df686767fba21
Author:        Paul E. McKenney <paulmck@xxxxxxxxxx>
AuthorDate:    Thu, 23 Jul 2020 15:53:02 -07:00
Committer:     Paul E. McKenney <paulmck@xxxxxxxxxx>
CommitterDate: Mon, 24 Aug 2020 18:38:38 -07:00

scftorture: Add cond_resched() to test loop

Although the test loop does randomly delay, which would provide quiescent
states and so forth, it is possible for there to be a series of long
smp_call_function*() handler runtimes with no delays, which results in
softlockup and RCU CPU stall warning messages.  This commit therefore
inserts a cond_resched() into the main test loop.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
 kernel/scftorture.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/scftorture.c b/kernel/scftorture.c
index fc22bcc..554a521 100644
--- a/kernel/scftorture.c
+++ b/kernel/scftorture.c
@@ -420,6 +420,7 @@ static int scftorture_invoker(void *arg)
 			set_cpus_allowed_ptr(current, cpumask_of(cpu));
 			was_offline = false;
 		}
+		cond_resched();
 	} while (!torture_must_stop());
 
 	VERBOSE_SCFTORTOUT("scftorture_invoker %d ended", scfp->cpu);