[PATCH] prinkt/nbcon: Add a scheduling point to nbcon_kthread_func().

From: Sebastian Andrzej Siewior
Date: Thu Jun 20 2024 - 05:43:11 EST


Constant printing can lead to a CPU hog in nbcon_kthread_func(). The
context is preemptible but on !PREEMPT kernels there is no explicit
preemption point which leads softlockup warnings.

Add an explicit preemption point in nbcon_kthread_func().

Reported-by: Derek Barbosa <debarbos@xxxxxxxxxx>
Link: https://lore.kernel.org/ZnHF5j1DUDjN1kkq@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
kernel/printk/nbcon.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c
index bb9689f94d302..0813ce88a49c5 100644
--- a/kernel/printk/nbcon.c
+++ b/kernel/printk/nbcon.c
@@ -1119,6 +1119,7 @@ static int nbcon_kthread_func(void *__console)
}

console_srcu_read_unlock(cookie);
+ cond_resched();

} while (backlog);

--
2.45.2