[PATCH v5.10] cpufreq: scmi: Fix null-ptr-deref in scmi_cpufreq_get_rate()

[PATCH v5.10] cpufreq: scmi: Fix null-ptr-deref in scmi_cpufreq_get_rate()

[Shivani Agarwal]

From: Henry Martin <bsdhenrymartin@gmail.com>

[ Upstream commit 484d3f15cc6cbaa52541d6259778e715b2c83c54 ]

cpufreq_cpu_get_raw() can return NULL when the target CPU is not present
in the policy->cpus mask. scmi_cpufreq_get_rate() does not check for
this case, which results in a NULL pointer dereference.

Add NULL check after cpufreq_cpu_get_raw() to prevent this issue.

Fixes: 99d6bdf33877 ("cpufreq: add support for CPU DVFS based on SCMI message protocol")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[Shivani: Modified to apply on 5.10.y]
Signed-off-by: Shivani Agarwal <shivani.agarwal@broadcom.com>
---
 drivers/cpufreq/scmi-cpufreq.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c
index bb1389f27..6b65d537c 100644
--- a/drivers/cpufreq/scmi-cpufreq.c
+++ b/drivers/cpufreq/scmi-cpufreq.c
@@ -29,12 +29,18 @@ static const struct scmi_handle *handle;
 
 static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
 {
-	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
+	struct cpufreq_policy *policy;
+	struct scmi_data *priv;
 	const struct scmi_perf_ops *perf_ops = handle->perf_ops;
-	struct scmi_data *priv = policy->driver_data;
 	unsigned long rate;
 	int ret;
 
+	policy = cpufreq_cpu_get_raw(cpu);
+	if (unlikely(!policy))
+		return 0;
+
+	priv = policy->driver_data;
+
 	ret = perf_ops->freq_get(handle, priv->domain_id, &rate, false);
 	if (ret)
 		return 0;
-- 
2.40.4

Patch "cpufreq: scmi: Fix null-ptr-deref in scmi_cpufreq_get_rate()" has been added to the 5.10-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    cpufreq: scmi: Fix null-ptr-deref in scmi_cpufreq_get_rate()

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     cpufreq-scmi-fix-null-ptr-deref-in-scmi_cpufreq_get_rate.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From stable+bounces-204627-greg=kroah.com@vger.kernel.org Mon Jan  5 11:19:06 2026
From: Shivani Agarwal <shivani.agarwal@broadcom.com>
Date: Mon,  5 Jan 2026 01:57:01 -0800
Subject: cpufreq: scmi: Fix null-ptr-deref in scmi_cpufreq_get_rate()
To: stable@vger.kernel.org, gregkh@linuxfoundation.org
Cc: sudeep.holla@arm.com, cristian.marussi@arm.com, rafael@kernel.org, viresh.kumar@linaro.org, arm-scmi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, ajay.kaher@broadcom.com, alexey.makhalov@broadcom.com, vamsi-krishna.brahmajosyula@broadcom.com, yin.ding@broadcom.com, tapas.kundu@broadcom.com, Henry Martin <bsdhenrymartin@gmail.com>, Sasha Levin <sashal@kernel.org>, Shivani Agarwal <shivani.agarwal@broadcom.com>
Message-ID: <20260105095701.659420-1-shivani.agarwal@broadcom.com>

From: Henry Martin <bsdhenrymartin@gmail.com>

[ Upstream commit 484d3f15cc6cbaa52541d6259778e715b2c83c54 ]

cpufreq_cpu_get_raw() can return NULL when the target CPU is not present
in the policy->cpus mask. scmi_cpufreq_get_rate() does not check for
this case, which results in a NULL pointer dereference.

Add NULL check after cpufreq_cpu_get_raw() to prevent this issue.

Fixes: 99d6bdf33877 ("cpufreq: add support for CPU DVFS based on SCMI message protocol")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[Shivani: Modified to apply on 5.10.y]
Signed-off-by: Shivani Agarwal <shivani.agarwal@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/cpufreq/scmi-cpufreq.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/drivers/cpufreq/scmi-cpufreq.c
+++ b/drivers/cpufreq/scmi-cpufreq.c
@@ -29,12 +29,18 @@ static const struct scmi_handle *handle;
 
 static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
 {
-	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
+	struct cpufreq_policy *policy;
+	struct scmi_data *priv;
 	const struct scmi_perf_ops *perf_ops = handle->perf_ops;
-	struct scmi_data *priv = policy->driver_data;
 	unsigned long rate;
 	int ret;
 
+	policy = cpufreq_cpu_get_raw(cpu);
+	if (unlikely(!policy))
+		return 0;
+
+	priv = policy->driver_data;
+
 	ret = perf_ops->freq_get(handle, priv->domain_id, &rate, false);
 	if (ret)
 		return 0;


Patches currently in stable-queue which might be from shivani.agarwal@broadcom.com are

queue-5.10/usb-xhci-move-link-chain-bit-quirk-checks-into-one-helper-function.patch
queue-5.10/crypto-af_alg-zero-initialize-memory-allocated-via-sock_kmalloc.patch
queue-5.10/rdma-core-fix-kasan-slab-use-after-free-read-in-ib_register_device-problem.patch
queue-5.10/ovl-use-buf-flexible-array-for-memcpy-destination.patch
queue-5.10/cpufreq-scmi-fix-null-ptr-deref-in-scmi_cpufreq_get_rate.patch
queue-5.10/drm-vmwgfx-fix-a-null-ptr-access-in-the-cursor-snooper.patch
queue-5.10/scsi-iscsi_tcp-fix-uaf-during-logout-when-accessing-the-shost-ipaddress.patch
queue-5.10/usb-xhci-apply-the-link-chain-quirk-on-nec-isoc-endpoints.patch
queue-5.10/scsi-iscsi-move-pool-freeing.patch