[tip: timers/core] tick/rcu: Fix bogus ratelimit condition

From: tip-bot2 for Wen Yang
Date: Sat Jun 10 2023 - 08:45:47 EST


The following commit has been merged into the timers/core branch of tip:

Commit-ID: 5579a8a8f15bd08b731a015630daca6ccd0f8a14
Gitweb: https://git.kernel.org/tip/5579a8a8f15bd08b731a015630daca6ccd0f8a14
Author: Wen Yang <wenyang.linux@xxxxxxxxxxx>
AuthorDate: Fri, 05 May 2023 00:12:53 +08:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Sat, 10 Jun 2023 14:36:17 +02:00

tick/rcu: Fix bogus ratelimit condition

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: 0345691b24c0 ("tick/rcu: Stop allowing RCU_SOFTIRQ in idle")
Signed-off-by: Wen Yang <wenyang.linux@xxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/tencent_5AAA3EEAB42095C9B7740BE62FBF9A67E007@xxxxxx

---
kernel/time/tick-sched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 5225467..8905505 100644
--- 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 */