[tip:sched/core] sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu - tip-bot for Joel Fernandes (Google)

From: "tip-bot for Joel Fernandes (Google)" <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: morten.rasmussen@arm.com, josh@joshtriplett.org,
	jiangshanlai@gmail.com, mingo@kernel.org,
	torvalds@linux-foundation.org, joel@joelfernandes.org,
	rostedt@goodmis.org, linux-kernel@vger.kernel.org, efault@gmx.de,
	mathieu.desnoyers@efficios.com, hpa@zytor.com,
	tglx@linutronix.de, peterz@infradead.org,
	luc.vanoostenryck@gmail.com, paulmck@linux.ibm.com
Subject: [tip:sched/core] sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu
Date: Wed, 3 Apr 2019 01:39:19 -0700	[thread overview]
Message-ID: <tip-8f9affdf4094bde418a0dbd8b52bb503ee486469@git.kernel.org> (raw)
In-Reply-To: <20190321003426.160260-2-joel@joelfernandes.org>

Commit-ID:  8f9affdf4094bde418a0dbd8b52bb503ee486469
Gitweb:     https://git.kernel.org/tip/8f9affdf4094bde418a0dbd8b52bb503ee486469
Author:     Joel Fernandes (Google) <joel@joelfernandes.org>
AuthorDate: Wed, 20 Mar 2019 20:34:23 -0400
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 3 Apr 2019 09:51:01 +0200

sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu

Recently I added an RCU annotation check to rcu_assign_pointer(). All
pointers assigned to RCU protected data are to be annotated with __rcu
inorder to be able to use rcu_assign_pointer() similar to checks in
other RCU APIs.

This resulted in a sparse error:

  kernel//sched/cpufreq.c:41:9: sparse: error: incompatible types in comparison expression (different address spaces)

Fix this by annotating cpufreq_update_util_data pointer with __rcu. This
will also help sparse catch any future RCU misuage bugs.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
[ From an RCU perspective. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: keescook@chromium.org
Cc: kernel-hardening@lists.openwall.com
Cc: kernel-team@android.com
Link: https://lkml.kernel.org/r/20190321003426.160260-2-joel@joelfernandes.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/cpufreq.c | 2 +-
 kernel/sched/sched.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c
index 835671f0f917..b5dcd1d83c7f 100644
--- a/kernel/sched/cpufreq.c
+++ b/kernel/sched/cpufreq.c
@@ -7,7 +7,7 @@
  */
 #include "sched.h"
 
-DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);
+DEFINE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
 
 /**
  * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer.
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index efa686eeff26..713715dd00cf 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2185,7 +2185,7 @@ static inline u64 irq_time_read(int cpu)
 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
 
 #ifdef CONFIG_CPU_FREQ
-DECLARE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);
+DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
 
 /**
  * cpufreq_update_util - Take a note about CPU utilization changes.
