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; -- 1.8.3.1