Sorry, please ignore this patch.
On 2017/7/21 16:39, Kefeng Wang wrote:
> From: Catalin Marinas <catalin.marinas@xxxxxxx>
>
> 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@xxxxxxx>
> Cc: 4.5+ <stable@xxxxxxxxxxxxxxx> # 4.5+
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
>
> 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;