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authorPaul Gortmaker <paul.gortmaker@windriver.com>2021-12-06 09:59:50 -0500
committerThomas Gleixner <tglx@linutronix.de>2022-04-10 12:23:34 +0200
commit40e97e42961f8c6cc7bd5fe67cc18417e02d78f1 (patch)
tree4ba3c93934475c5c40ffa8c80e1edb343df6611b /kernel/time
parentc54bc0fc84214b203f7a0ebfd1bd308ce2abe920 (diff)
downloadlinux-40e97e42961f8c6cc7bd5fe67cc18417e02d78f1.tar.gz
tick/nohz: Use WARN_ON_ONCE() to prevent console saturation
While running some testing on code that happened to allow the variable
tick_nohz_full_running to get set but with no "possible" NOHZ cores to
back up that setting, this warning triggered:

        if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
                WARN_ON(tick_nohz_full_running);

The console was overwhemled with an endless stream of one WARN per tick
per core and there was no way to even see what was going on w/o using a
serial console to capture it and then trace it back to this.

Change it to WARN_ON_ONCE().

Fixes: 08ae95f4fd3b ("nohz_full: Allow the boot CPU to be nohz_full")
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211206145950.10927-3-paul.gortmaker@windriver.com

Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/tick-sched.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 2d76c91b85de..3506f6ed790c 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -188,7 +188,7 @@ static void tick_sched_do_timer(struct tick_sched *ts, ktime_t now)
 	 */
 	if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE)) {
 #ifdef CONFIG_NO_HZ_FULL
-		WARN_ON(tick_nohz_full_running);
+		WARN_ON_ONCE(tick_nohz_full_running);
 #endif
 		tick_do_timer_cpu = cpu;
 	}