From ed00869011ae71ae59d299be8aeae8dd0ea21365 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Thu, 20 Jun 2024 11:21:13 +0200 Subject: [PATCH] prinkt/nbcon: Add a scheduling point to nbcon_kthread_func(). BugLink: https://bugs.launchpad.net/bugs/2102249 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 Link: https://lore.kernel.org/ZnHF5j1DUDjN1kkq@debarbos-thinkpadt14sgen2i.remote.csb Reviewed-by: John Ogness Acked-by: Andrew Halaney Tested-by: Andrew Halaney Acked-by: Derek Barbosa Tested-by: Derek Barbosa Link: https://lore.kernel.org/r/20240620094300.YJlW043f@linutronix.de Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Clark Williams (cherry picked from PREEMPT_RT 6.6.78-rt51) Acked-by: Benjamin Wheeler Acked-by: Massimiliano Pellizzer Signed-off-by: Kevin Becker --- kernel/printk/nbcon.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c index 932b888aa4c3..b7a4d3be65a5 100644 --- a/kernel/printk/nbcon.c +++ b/kernel/printk/nbcon.c @@ -1117,6 +1117,7 @@ wait_for_event: } console_srcu_read_unlock(cookie); + cond_resched(); } while (backlog);