From: Rafael J. Wysocki Date: Fri, 19 Sep 2025 11:22:20 +0000 (+0200) Subject: cpuidle: Fail cpuidle device registration if there is one already X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7b1b7961170e4fcad488755e5ffaaaf9bd527e8f;p=users%2Fhch%2Fmisc.git cpuidle: Fail cpuidle device registration if there is one already Refuse to register a cpuidle device if the given CPU has a cpuidle device already and print a message regarding it. Without this, an attempt to register a new cpuidle device without unregistering the existing one leads to the removal of the existing cpuidle device without removing its sysfs interface. Signed-off-by: Rafael J. Wysocki --- diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 0835da449db8..56132e843c99 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -635,8 +635,14 @@ static void __cpuidle_device_init(struct cpuidle_device *dev) static int __cpuidle_register_device(struct cpuidle_device *dev) { struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); + unsigned int cpu = dev->cpu; int i, ret; + if (per_cpu(cpuidle_devices, cpu)) { + pr_info("CPU%d: cpuidle device already registered\n", cpu); + return -EEXIST; + } + if (!try_module_get(drv->owner)) return -EINVAL; @@ -648,7 +654,7 @@ static int __cpuidle_register_device(struct cpuidle_device *dev) dev->states_usage[i].disable |= CPUIDLE_STATE_DISABLED_BY_USER; } - per_cpu(cpuidle_devices, dev->cpu) = dev; + per_cpu(cpuidle_devices, cpu) = dev; list_add(&dev->device_list, &cpuidle_detected_devices); ret = cpuidle_coupled_register_device(dev);