tick/rcu: Fix bogus ratelimit condition

taskset · KAGA-KOKO · commit a7e282c77785 · 2023-06-18T22:41:53.000+02:00
The ratelimit logic in report_idle_softirq() is broken because the exit condition is always true: static int ratelimit; if (ratelimit < 10) return false; ---> always returns here ratelimit++; ---> no chance to run Make it check for >= 10 instead. Fixes: 0345691 ("tick/rcu: Stop allowing RCU_SOFTIRQ in idle") Signed-off-by: Wen Yang <wenyang.linux@foxmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/tencent_5AAA3EEAB42095C9B7740BE62FBF9A67E007@qq.com
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
@@ -1030,7 +1030,7 @@ static bool report_idle_softirq(void)
 			return false;
 	}
 
-	if (ratelimit < 10)
+	if (ratelimit >= 10)
 		return false;
 
 	/* On RT, softirqs handling may be waiting on some lock */

Original file line number	Diff line number	Diff line change
`@@ -1030,7 +1030,7 @@ static bool report_idle_softirq(void)`
`1030`	`1030`	`return false;`
`1031`	`1031`	`}`
`1032`	`1032`
`1033`		`- if (ratelimit < 10)`
	`1033`	`+ if (ratelimit >= 10)`
`1034`	`1034`	`return false;`
`1035`	`1035`
`1036`	`1036`	`/* On RT, softirqs handling may be waiting on some lock */`