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 <debarbos@redhat.com>
Link: https://lore.kernel.org/ZnHF5j1DUDjN1kkq@debarbos-thinkpadt14sgen2i.remote.csb
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Acked-by: Andrew Halaney <ahalaney@redhat.com>
Tested-by: Andrew Halaney <ahalaney@redhat.com>
Acked-by: Derek Barbosa <debarbos@redhat.com>
Tested-by: Derek Barbosa <debarbos@redhat.com>
Link: https://lore.kernel.org/r/20240620094300.YJlW043f@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Clark Williams <clark.williams@gmail.com>
(cherry picked from PREEMPT_RT 6.6.78-rt51)
Acked-by: Benjamin Wheeler <benjamin.wheeler@canonical.com>
Acked-by: Massimiliano Pellizzer <massimiliano.pellizzer@canonical.com>
Signed-off-by: Kevin Becker <kevin.becker@canonical.com>

This commit is contained in:

Sebastian Andrzej Siewior

2024-06-20 11:21:13 +02:00

committed by

Kevin Becker

parent 48e860dd01

commit ed00869011

1 changed files with 1 additions and 0 deletions

									
										kernel/printk/nbcon.c
									
		+1
		
												View File
												
				@@ -1117,6 +1117,7 @@ wait_for_event:

						}

						console_srcu_read_unlock(cookie);

						cond_resched();

					} while (backlog);