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From: Sean V Kelley <skelley@nvidia.com>
To: rafael@kernel.org
Cc: lenb@kernel.org, pprakash@codeaurora.org, gautham.shenoy@amd.com,
	jamien@nvidia.com, mochs@nvidia.com, linux-acpi@vger.kernel.org,
	linux-kernel@vger.kernel.org, Sean V Kelley <skelley@nvidia.com>
Subject: [PATCH v2] ACPI: CPPC: Fix remaining for_each_possible_cpu() to use online CPUs
Date: Wed, 11 Feb 2026 21:22:54 +0000	[thread overview]
Message-ID: <20260211212254.30190-1-skelley@nvidia.com> (raw)

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>
---

Notes:
    v2: Also fix for_each_possible_cpu() in send_pcc_cmd() (Rafael)

 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 a09bdabaa804..0e6ffb188fe7 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -362,7 +362,7 @@ 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)
@@ -524,7 +524,7 @@ 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;
 
-- 
2.43.0


             reply	other threads:[~2026-02-11 21:23 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-11 21:22 Sean V Kelley [this message]
2026-02-12 11:44 ` [PATCH v2] ACPI: CPPC: Fix remaining for_each_possible_cpu() to use online CPUs Rafael J. Wysocki

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