[PATCH AUTOSEL 5.15 092/188] rcutorture: Avoid soft lockup during cpu stall

From: Sasha Levin
Date: Mon Jan 17 2022 - 22:48:28 EST


From: Wander Lairson Costa <wander@xxxxxxxxxx>

[ Upstream commit 5ff7c9f9d7e3e0f6db5b81945fa11b69d62f433a ]

If we use the module stall_cpu option, we may get a soft lockup warning
in case we also don't pass the stall_cpu_block option.

Introduce the stall_no_softlockup option to avoid a soft lockup on
cpu stall even if we don't use the stall_cpu_block option.

Signed-off-by: Wander Lairson Costa <wander@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/rcu/rcutorture.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 968696ace8f3f..f922937eb39ad 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -46,6 +46,7 @@
#include <linux/oom.h>
#include <linux/tick.h>
#include <linux/rcupdate_trace.h>
+#include <linux/nmi.h>

#include "rcu.h"

@@ -109,6 +110,8 @@ torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
torture_param(int, stall_cpu_holdoff, 10,
"Time to wait before starting stall (s).");
+torture_param(bool, stall_no_softlockup, false,
+ "Avoid softlockup warning during cpu stall.");
torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
torture_param(int, stall_gp_kthread, 0,
@@ -2052,6 +2055,8 @@ static int rcu_torture_stall(void *args)
#else
schedule_timeout_uninterruptible(HZ);
#endif
+ } else if (stall_no_softlockup) {
+ touch_softlockup_watchdog();
}
if (stall_cpu_irqsoff)
local_irq_enable();
--
2.34.1