linux-kernel - [GIT PULL] scheduler fix

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Message-ID: <Z9PywlnGNS7ctnh_@gmail.com>
Date: Fri, 14 Mar 2025 10:11:30 +0100
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, Peter Zijlstra <peterz@...radead.org>,
	Juri Lelli <juri.lelli@...hat.com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
	Daniel Bristot de Oliveira <bristot@...hat.com>,
	Valentin Schneider <vschneid@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Subject: [GIT PULL] scheduler fix

Linus,

Please pull the latest sched/urgent Git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched-urgent-2025-03-14

   # HEAD: f3fa0e40df175acd60b71036b9a1fd62310aec03 sched/clock: Don't define sched_clock_irqtime as static key

Fix a sleeping-while-atomic bug caused by a recent optimization
utilizing static keys that didn't consider that the
static_key_disable() call could be triggered in atomic context.

Revert the optimization.

 Thanks,

	Ingo

------------------>
Yafang Shao (1):
      sched/clock: Don't define sched_clock_irqtime as static key


 kernel/sched/cputime.c | 8 ++++----
 kernel/sched/sched.h   | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 5d9143dd0879..6dab4854c6c0 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -9,8 +9,6 @@
 
 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
 
-DEFINE_STATIC_KEY_FALSE(sched_clock_irqtime);
-
 /*
  * There are no locks covering percpu hardirq/softirq time.
  * They are only modified in vtime_account, on corresponding CPU
@@ -24,14 +22,16 @@ DEFINE_STATIC_KEY_FALSE(sched_clock_irqtime);
  */
 DEFINE_PER_CPU(struct irqtime, cpu_irqtime);
 
+int sched_clock_irqtime;
+
 void enable_sched_clock_irqtime(void)
 {
-	static_branch_enable(&sched_clock_irqtime);
+	sched_clock_irqtime = 1;
 }
 
 void disable_sched_clock_irqtime(void)
 {
-	static_branch_disable(&sched_clock_irqtime);
+	sched_clock_irqtime = 0;
 }
 
 static void irqtime_account_delta(struct irqtime *irqtime, u64 delta,
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index c8512a9fb022..023b844159c9 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -3259,11 +3259,11 @@ struct irqtime {
 };
 
 DECLARE_PER_CPU(struct irqtime, cpu_irqtime);
-DECLARE_STATIC_KEY_FALSE(sched_clock_irqtime);
+extern int sched_clock_irqtime;
 
 static inline int irqtime_enabled(void)
 {
-	return static_branch_likely(&sched_clock_irqtime);
+	return sched_clock_irqtime;
 }
 
 /*