[hulk-4.1-next,1/2] cpuidle: Do not access cpuidle_devices when !CONFIG_CPU_IDLE

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  • [hulk-4.1-next,1/2] cpuidle: Do not access cpuidle_devices when !CONFIG_CPU_IDLE
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Commit Message

Kefeng Wang July 21, 2017, 8:39 a.m.
From: Catalin Marinas <catalin.marinas@arm.com>


mainline inclusion
from mainline-4.7
commit 9bd616e3dbedfc103f158197c8ad93678849b1ed
category: bugfix
bugzilla: 3312
DTS: NA
CVE: NA

-------------------------------------------------

The cpuidle_devices per-CPU variable is only defined when CPU_IDLE is
enabled. Commit c8cc7d4de7a4 ("sched/idle: Reorganize the idle loop")
removed the #ifdef CONFIG_CPU_IDLE around cpuidle_idle_call() with the
compiler optimising away __this_cpu_read(cpuidle_devices). However, with
CONFIG_UBSAN && !CONFIG_CPU_IDLE, this optimisation no longer happens
and the kernel fails to link since cpuidle_devices is not defined.

This patch introduces an accessor function for the current CPU cpuidle
device (returning NULL when !CONFIG_CPU_IDLE) and uses it in
cpuidle_idle_call().

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Cc: 4.5+ <stable@vger.kernel.org> # 4.5+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>


Conflicts:
	include/linux/cpuidle.h
---
 include/linux/cpuidle.h | 3 +++
 kernel/sched/idle.c     | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

-- 
1.8.3.1

Comments

Kefeng Wang July 21, 2017, 9:08 a.m. | #1
Sorry, please ignore this patch.


On 2017/7/21 16:39, Kefeng Wang wrote:
> From: Catalin Marinas <catalin.marinas@arm.com>

>

> mainline inclusion

> from mainline-4.7

> commit 9bd616e3dbedfc103f158197c8ad93678849b1ed

> category: bugfix

> bugzilla: 3312

> DTS: NA

> CVE: NA

>

> -------------------------------------------------

>

> The cpuidle_devices per-CPU variable is only defined when CPU_IDLE is

> enabled. Commit c8cc7d4de7a4 ("sched/idle: Reorganize the idle loop")

> removed the #ifdef CONFIG_CPU_IDLE around cpuidle_idle_call() with the

> compiler optimising away __this_cpu_read(cpuidle_devices). However, with

> CONFIG_UBSAN && !CONFIG_CPU_IDLE, this optimisation no longer happens

> and the kernel fails to link since cpuidle_devices is not defined.

>

> This patch introduces an accessor function for the current CPU cpuidle

> device (returning NULL when !CONFIG_CPU_IDLE) and uses it in

> cpuidle_idle_call().

>

> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

> Cc: 4.5+ <stable@vger.kernel.org> # 4.5+

> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>

>

> Conflicts:

> 	include/linux/cpuidle.h

> ---

>  include/linux/cpuidle.h | 3 +++

>  kernel/sched/idle.c     | 2 +-

>  2 files changed, 4 insertions(+), 1 deletion(-)

>

> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h

> index 9c5e892..111ead2 100644

> --- a/include/linux/cpuidle.h

> +++ b/include/linux/cpuidle.h

> @@ -157,6 +157,8 @@ extern int cpuidle_enter_freeze(struct cpuidle_driver *drv,

>  				struct cpuidle_device *dev);

>  

>  extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);

> +static inline struct cpuidle_device *cpuidle_get_device(void)

> +{return __this_cpu_read(cpuidle_devices); }

>  #else

>  static inline void disable_cpuidle(void) { }

>  static inline bool cpuidle_not_available(struct cpuidle_driver *drv,

> @@ -198,6 +200,7 @@ static inline int cpuidle_enter_freeze(struct cpuidle_driver *drv,

>  {return -ENODEV; }

>  static inline struct cpuidle_driver *cpuidle_get_cpu_driver(

>  	struct cpuidle_device *dev) {return NULL; }

> +static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }

>  #endif

>  

>  #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED

> diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c

> index fefcb1f..437d577e 100644

> --- a/kernel/sched/idle.c

> +++ b/kernel/sched/idle.c

> @@ -78,7 +78,7 @@ void __weak arch_cpu_idle(void)

>   */

>  static void cpuidle_idle_call(void)

>  {

> -	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);

> +	struct cpuidle_device *dev = cpuidle_get_device();

>  	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);

>  	int next_state, entered_state;

>  	bool reflect;

Patch

diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 9c5e892..111ead2 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -157,6 +157,8 @@  extern int cpuidle_enter_freeze(struct cpuidle_driver *drv,
 				struct cpuidle_device *dev);
 
 extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
+static inline struct cpuidle_device *cpuidle_get_device(void)
+{return __this_cpu_read(cpuidle_devices); }
 #else
 static inline void disable_cpuidle(void) { }
 static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
@@ -198,6 +200,7 @@  static inline int cpuidle_enter_freeze(struct cpuidle_driver *drv,
 {return -ENODEV; }
 static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
 	struct cpuidle_device *dev) {return NULL; }
+static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
 #endif
 
 #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index fefcb1f..437d577e 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -78,7 +78,7 @@  void __weak arch_cpu_idle(void)
  */
 static void cpuidle_idle_call(void)
 {
-	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
+	struct cpuidle_device *dev = cpuidle_get_device();
 	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
 	int next_state, entered_state;
 	bool reflect;