[PATCH 6.1 210/232] ACPI: CPPC: Fix remaining for_each_possible_cpu() to use online CPUs

Sasha Levin
2026-02-28T18:14:26Z

From: Sean V Kelley <skelley@nvidia.com>

[ Upstream commit 56eb0c0ed345da7815274aa821a8546a073d7e97 ]

per_cpu(cpc_desc_ptr, cpu) object is initialized for only the online
CPUs via acpi_soft_cpu_online() --> __acpi_processor_start() -->
acpi_cppc_processor_probe().

However, send_pcc_cmd() and acpi_get_psd_map() still iterate over all
possible CPUs. In acpi_get_psd_map(), encountering an offline CPU
returns -EFAULT, causing cppc_cpufreq initialization to fail.

This breaks systems booted with "nosmt" or "nosmt=force".

Fix by using for_each_online_cpu() in both functions.

Fixes: 80b8286aeec0 ("ACPI / CPPC: support for batching CPPC requests")
Signed-off-by: Sean V Kelley <skelley@nvidia.com>
Link: https://patch.msgid.link/20260211212254.30190-1-skelley@nvidia.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/acpi/cppc_acpi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index c763c25424663..4382340fd9778 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -342,7 +342,7 @@ static int send_pcc_cmd(int pcc_ss_id, u16 cmd)
end:
if (cmd == CMD_WRITE) {
if (unlikely(ret)) {
- for_each_possible_cpu(i) {
+ for_each_online_cpu(i) {
struct cpc_desc *desc = per_cpu(cpc_desc_ptr, i);

if (!desc)
@@ -504,7 +504,7 @@ int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data)
else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ANY;

- for_each_possible_cpu(i) {
+ for_each_online_cpu(i) {
if (i == cpu)
continue;

--
2.51.0