The old states may not be usable any more if get power information
failed in power notify. The ACPI idle should be disabled entirely.

Fixes: f427e5f1cf75 ("ACPI / processor: Get power info before updating the C-states")
Signed-off-by: Huisong Li <lihuisong@huawei.com>
---
 drivers/acpi/processor_idle.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 5f86297c8b23..cd4d1d8d70b0 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1298,6 +1298,7 @@ int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
 	int cpu;
 	struct acpi_processor *_pr;
 	struct cpuidle_device *dev;
+	int ret = 0;
 
 	if (disabled_by_idle_boot_param())
 		return 0;
@@ -1326,27 +1327,44 @@ int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
 			cpuidle_disable_device(dev);
 		}
 
-		/* Populate Updated C-state information */
-		acpi_processor_get_power_info(pr);
+		/*
+		 * Update C-state information based on new power information.
+		 *
+		 * The same idle state is used for all CPUs.
+		 * The old idle state may not be usable anymore if fail to get
+		 * ACPI power information of CPU0.
+		 * The cpuidle of all CPUs should be disabled.
+		 */
+		ret = acpi_processor_get_power_info(pr);
+		if (ret) {
+			/* Ensure cpuidle of offline CPUs are inavaliable. */
+			disable_cpuidle();
+			pr_err("Get processor-%u power information failed, disable cpuidle of all CPUs\n",
+			       pr->id);
+			goto release_lock;
+		}
+
 		acpi_processor_setup_cpuidle_states(pr);
+		enable_cpuidle();
 
 		/* Enable all cpuidle devices */
 		for_each_online_cpu(cpu) {
 			_pr = per_cpu(processors, cpu);
 			if (!_pr || !_pr->flags.power_setup_done)
 				continue;
-			acpi_processor_get_power_info(_pr);
-			if (_pr->flags.power) {
+			ret = acpi_processor_get_power_info(_pr);
+			if (!ret && _pr->flags.power) {
 				dev = per_cpu(acpi_cpuidle_device, cpu);
 				acpi_processor_setup_cpuidle_dev(_pr, dev);
 				cpuidle_enable_device(dev);
 			}
 		}
+release_lock:
 		cpuidle_resume_and_unlock();
 		cpus_read_unlock();
 	}
 
-	return 0;
+	return ret;
 }
 
 void acpi_processor_register_idle_driver(void)
-- 
2.33.0

Hi Huisong,

kernel test robot noticed the following build errors:

[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on rafael-pm/bleeding-edge linus/master v6.18-rc7 next-20251127]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Huisong-Li/cpuidle-Add-enable_cpuidle-interface/20251125-153615
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link:    https://lore.kernel.org/r/20251125072933.3706006-3-lihuisong%40huawei.com
patch subject: [PATCH 2/3] ACPI: processor: idle: Disable ACPI idle if get power information failed in power notify
config: riscv-randconfig-001-20251127 (https://download.01.org/0day-ci/archive/20251127/202511272227.w1fgoiKQ-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 12.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251127/202511272227.w1fgoiKQ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511272227.w1fgoiKQ-lkp@intel.com/

All errors (new ones prefixed by >>, old ones prefixed by <<):

>> ERROR: modpost: "enable_cpuidle" [drivers/acpi/processor.ko] undefined!
>> ERROR: modpost: "disable_cpuidle" [drivers/acpi/processor.ko] undefined!

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki