* [PATCH] tick/rcu: fix an issue in the report_idle_softirq function
@ 2023-05-04 16:12 wenyang.linux
2023-06-10 12:45 ` [tip: timers/core] tick/rcu: Fix bogus ratelimit condition tip-bot2 for Wen Yang
2023-06-18 20:49 ` tip-bot2 for Wen Yang
0 siblings, 2 replies; 3+ messages in thread
From: wenyang.linux @ 2023-05-04 16:12 UTC (permalink / raw)
To: Frederic Weisbecker, Thomas Gleixner, Ingo Molnar
Cc: Wen Yang, Frederic Weisbecker, Peter Zijlstra, Paul E . McKenney,
Paul Menzel, linux-kernel
From: Wen Yang <wenyang.linux@foxmail.com>
Commit 0345691b24c0 ("tick/rcu: Stop allowing RCU_SOFTIRQ in idle")
introduced the function report_idle_softirq, but the ratelimit logic
was broken because it is a static variable that returned before being
incremented, as follows:
static int ratelimit;
...
if (ratelimit < 10)
return false; ---> always return here
...
ratelimit++; ---> no chance to run
We need to adjust the original "< 10" logic to ">= 10".
Fixes: 0345691b24c0 ("tick/rcu: Stop allowing RCU_SOFTIRQ in idle")
Signed-off-by: Wen Yang <wenyang.linux@foxmail.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org
---
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 a46506f7ec6d..8891ad1d9a11 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -1035,7 +1035,7 @@ 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 */
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [tip: timers/core] tick/rcu: Fix bogus ratelimit condition
2023-05-04 16:12 [PATCH] tick/rcu: fix an issue in the report_idle_softirq function wenyang.linux
@ 2023-06-10 12:45 ` tip-bot2 for Wen Yang
2023-06-18 20:49 ` tip-bot2 for Wen Yang
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot2 for Wen Yang @ 2023-06-10 12:45 UTC (permalink / raw)
To: linux-tip-commits; +Cc: Wen Yang, Thomas Gleixner, x86, linux-kernel
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@foxmail.com>
AuthorDate: Fri, 05 May 2023 00:12:53 +08:00
Committer: Thomas Gleixner <tglx@linutronix.de>
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@foxmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/tencent_5AAA3EEAB42095C9B7740BE62FBF9A67E007@qq.com
---
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 */
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [tip: timers/core] tick/rcu: Fix bogus ratelimit condition
2023-05-04 16:12 [PATCH] tick/rcu: fix an issue in the report_idle_softirq function wenyang.linux
2023-06-10 12:45 ` [tip: timers/core] tick/rcu: Fix bogus ratelimit condition tip-bot2 for Wen Yang
@ 2023-06-18 20:49 ` tip-bot2 for Wen Yang
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot2 for Wen Yang @ 2023-06-18 20:49 UTC (permalink / raw)
To: linux-tip-commits; +Cc: Wen Yang, Thomas Gleixner, x86, linux-kernel
The following commit has been merged into the timers/core branch of tip:
Commit-ID: a7e282c77785c7eabf98836431b1f029481085ad
Gitweb: https://git.kernel.org/tip/a7e282c77785c7eabf98836431b1f029481085ad
Author: Wen Yang <wenyang.linux@foxmail.com>
AuthorDate: Fri, 05 May 2023 00:12:53 +08:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sun, 18 Jun 2023 22:41:53 +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@foxmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/tencent_5AAA3EEAB42095C9B7740BE62FBF9A67E007@qq.com
---
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 */
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-06-18 20:50 UTC | newest]
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2023-05-04 16:12 [PATCH] tick/rcu: fix an issue in the report_idle_softirq function wenyang.linux
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